Chapter 17: Dermatology

Since dermatology is a visual science, take a look at pictures at www.dermnet.org.nz/sitemap.html, or www.dermnet.com. See Table 17-1 for commonly used dermatology terms.

A 37-year-old white female presents to clinic for her annual well adult physical examination. After a complete skin examination, you find a suspicious lesion on her back (Fig. 17-1). It measures 16 mm × 8 mm. She has approximately 20 nevi that appear normal. The patient reports never performing self-skin examinations and does not know if the lesion in question is new. She denies any symptomatic lesions. Her family history is remarkable for "skin cancer" on her father's side. Many family members have "tons of moles." She frequented a tanning parlor in college (too much free time … probably majored in communications) and occasionally still does so before social events (didn't learn much about skin health in college).

FIGURE 17-1.

Question 17.1.1 How do you evaluate the lesion?

A) Take a photograph and see her back in 2 months

B) Take a shallow shave biopsy of the lesion

C) Excise the entire lesion with 1- to 2-mm margins

D) Excise the entire lesion with 3-cm margins

E) All of the above are equally valid approaches

Answer 17.1.1 The correct answer is "C." This lesion is worrisome for malignant melanoma because of the different pigmentation colors and irregular borders. Any time you suspect melanoma, you are obligated to completely remove the entire lesion and send it for pathology either with a punch biopsy or excisional biopsy. "A" is not an option; if you suspect melanoma, the earlier you make the diagnosis the better. A shave biopsy ("B") is also not recommended because the shave biopsy is often too shallow and the deep margins are not visible, which is the most important factor in staging melanoma. Partial removal of a lesion may lead to a sampling error, which is why excisional biopsy with narrow (e.g., 1–2 mm) margins is preferred. "D" is preferable to "A" and "B"; however, it would be unnecessary to remove the lesion with such large margins when the histopathology is not yet known.

You excise the entire lesion with a small border. The pathology report reveals a malignant melanoma.

Question 17.1.2 Which of the following lesion characteristics will determine your patient's prognosis?

A) The depth and ulceration

B) The diameter of the lesion

C) The number of colors in the lesion

D) Whether or not it arose in a pre-existing mole

E) The number of lymphocytes in the biopsy

Answer 17.1.2 The correct answer is "A." As alluded to previously, the depth of the melanoma is the most important prognostic indicator. Breslow tumor thickness is most commonly used to arrive at a prognosis. Breslow tumor thickness measures the depth of the melanoma from the granular layer in the epidermis to the base of the melanoma in millimeters. A thinner melanoma correlates with a better prognosis and melanomas with a Breslow depth 0.75 mm generally have the best prognosis. Ulceration is associated with more aggressive cancers and a poorer prognosis. Clark level (invasion based upon the anatomic structure of the skin) is still reported but is not as important in regards to prognosis as Breslow depth. The diameter of the lesion ("B," or the size observed on the skin) has not been associated with prognosis (e.g., superficial spreading melanoma may be large but generally carries a good prognosis). A very large, clinically atypical pigmented lesion can often be benign. Melanomas can also be of one color, many colors, or nonpigmented; color does not correlate with prognosis. Up to two-thirds of melanomas arise in normal skin. They can be just as aggressive as those arising from moles. The number of mitoses in a lesion can help predict the outcome; the more the mitoses, the worse the prognosis. The number of lymphocytes observed within a lesion can provide some information regarding the inflammatory response but does not possess the same prognostic value as the Breslow depth.

Question 17.1.3 In the United States in 2011, the lifetime risk of developing melanoma in a Caucasian female is approximately:

A) 1/10

B) 1/55

C) 1/105

D) 1/1500

Answer 17.1.3 The correct answer is "B." The lifetime probability of melanoma in the year 2011 for Caucasian females was approximately 1 in 55. Caucasian males in the United States fare worse, with a lifetime probability of 1/37.

Your biopsy reveals a malignant melanoma in situ. You excise the entire lesion with 0.5-cm margins. There is no penetration of the epidermis.

Question 17.1.4 What additional evaluation is necessary?

A) Chest x-ray

B) CT scan of the chest

C) Serum lactic acid dehydrogenase (LDH)

D) All of the above

E) None of the above

Answer 17.1.4 The correct answer is "E." If the melanoma has not penetrated the epidermis, it is referred to as a melanoma in situ. If excised with 0.5- to 1-cm margins, the long-term survival at 5 and 10 years approaches 100%. Therefore, any additional workup is not necessary according to the 2010 report from the American Joint Commission on Cancer. When the melanoma depth is greater than 1 mm, further workup is often performed. In general, chest radiography and a serum LDH level are recommended for malignant melanomas greater than 1 mm in depth, mostly to obtain a "baseline." Regarding a sentinel lymph node biopsy, although there is no proven therapeutic benefit, it can provide additional prognostic information for melanomas with a depth >1 mm. Serum LDH levels are usually positive in very advanced cases that have metastasized to bone or liver. A CT scan of the chest and pelvis and MRI of the brain can be ordered if metastatic disease is suspected, but these studies are not routinely recommended. Metastatic disease has not been reported with malignant melanoma in situ.

Question 17.1.5 Which of the following has NOT been associated with an increased risk of the development of melanoma?

A) Blistering sunburns in childhood

B) Sister with melanoma

C) Fair hair color

D) More than 50 moles on a person's body

E) Smoking

Answer 17.1.5 The correct answer is "E." A history of blistering sunburns, melanoma in first-degree relatives, fair hair, and more than 50 moles are all associated with an increased risk of developing melanoma. Also, high socioeconomic class and immunosuppression appear to be risk factors. Smoking has not yet been linked to malignant melanoma—unlike many other malignancies.

Question 17.1.6 The most common subtype of melanoma in people of African descent is:

A) Superficial spreading melanoma

B) Lentigo maligna melanoma

C) Nodular melanoma

D) Acral lentiginous melanoma

E) Amelanotic melanoma

Answer 17.1.6 The correct answer is "D." There are four classical subtypes of malignant melanoma. The subtype does not predict prognosis. Superficial spreading melanoma is the most common type in fair skin populations. It can occur at any site and clinically presents as a brown macule with irregular, notched borders. It grows radially (outward) initially. Nodular melanoma is the second most common type in fair skin individuals and, as the name suggests, is an exophytic nodule and often associated with deeper level of invasion and a vertical (downward) growth phase. Amelanotic melanoma is a subtype of nodular melanoma that presents with little to no pigment and may be red or pink in color. Lentigo maligna melanoma most often occurs in the elderly on sun-exposed areas, such as the face and hands and presents as a brown macule or patch with hue variations that spreads outward slowly. When there is dermal invasion, lentigo maligna is referred to as lentigo maligna melanoma. Acral lentiginous melanoma is the least common type in Caucasian populations but is the most common type in races with pigmented skin, such as people of African descent. Acral lentiginous melanoma occurs on the palms, soles, or near the nails. This is what killed Bob Marley.

Objectives: Did you learn to…

• Evaluate a patient with suspected melanoma?

• Describe how the prognosis of melanoma is determined?

• Recognize the lifetime risk of malignant melanoma in the United States?

• Identify risk factors for the development of melanoma?

• Recognize the four classic subtypes of melanoma and which are the most common in African and Caucasian populations?

A 22-year-old female presents with a pruritic rash on her elbows and extensor forearms. She's studying for finals, so she's been indoors for days eating Wheat Thins and drinking Mountain Dew. She has a history of celiac disease, but is otherwise healthy and takes no medications. On examination, she is afebrile and has 2- to 4-mm diameter vesicular lesions with numerous excoriations in a bilaterally symmetrical pattern on her extensor forearms, knees, and buttocks.

The most likely diagnosis is:

A) Dermatitis herpetiformis

B) Poison ivy (contact dermatitis)

C) Herpes simplex

D) Neurotic excoriations

E) Nerd elbow

The correct answer is "A." Dermatitis herpetiformis is the most common skin condition to occur in association with celiac disease (gluten enteropathy). This patient seems to have lapsed in her gluten-free diet, and her skin eruption has worsened as a result. Dermatitis herpetiformis presents with excoriated vesicles that are extremely pruritic. It can be confused with scabies. Often, only excoriations (and no blisters) are seen on examination. Dermatitis herpetiformis is also commonly symmetrical (as opposed to HSV) and may involve several body areas, most commonly extensor surfaces of the extremities. The cornerstone of treatment is a gluten-free diet. Dapsone can also help speed up resolution of the rash, but a strict gluten-free diet will also lead to disease resolution. In this case, "B" is unlikely due to symmetric and diffuse eruption without linear lesions and no reported exposure to poison ivy (we didn't tell you this, but her college is located in Antarctica, making poison ivy very unlikely). "C" is incorrect since the eruption is diffuse and there is no pain. Neurotic excoriations ("D") do not present with vesicles. If "E" were a real entity, the editors believe it would be an orthopedic disorder—some underuse atrophy of the joint maybe.

A 7-month-old male is brought to clinic for a "rash all over." Six weeks ago, his parents noticed him rubbing his legs against his crib and scratching his head frequently. They are concerned because they find blood on his sheets in the morning, and he has become increasingly irritable. He is eating and drinking normally. His past medical history is unremarkable. His father has sensitive skin and hay fever, but no one else in the family currently has a rash. He does not attend a daycare. On skin examination, you find lichenified and erythematous patches of skin with fissures and bleeding on the ventral heels, dorsal feet, hands, and a few areas on the scalp. His cheeks are bright red with scale. His diaper area is uninvolved and there are no lesions in the web spaces of the hands and feet.

Question 17.2.1 Based on the description, which of the following is the most likely diagnosis?

A) Seborrheic dermatitis

B) Atopic dermatitis

C) Scabies

D) Tinea corporis

E) Tinea versicolor

Answer 17.2.1 The correct answer is "B." The most likely diagnosis is atopic dermatitis, also known by the moniker eczema. Atopic dermatitis is characterized by an intensely pruritic eruption of the skin with associated dryness. A red rash subsequently develops. Atopic dermatitis is often referred to as the "itch that rashes." It occurs in characteristic locations. In younger infants, the cheeks and neck are involved. As they begin to crawl, their extensor surfaces are involved. The diaper area, because it is moist, is not usually involved. In older children, the flexural areas, such as the antecubital and popliteal fossae, are involved. Seborrheic dermatitis ("A") is common in infants (cradle cap) and is usually seen on the scalp and face, although it can involve the whole body. Seborrheic dermatitis is usually associated with a yellow, greasy scale and is less erythematous than atopic dermatitis. Scabies ("C") typically affects certain locations (web spaces, wrists, waist, etc.) and uncommonly involves the scalp, except in infants or immunocompromised patients. Also, in this question, he does not appear to have any exposure to scabies. Tinea corporis ("D") presents with a ring of advancing erythema and a central clearing ("ringworm"). Finally, tinea versicolor ("E") typically involves the trunk and extremities with hypo- or hyperpigmented patches with superficial scale. It does not involve the scalp, and is not very pruritic.

You diagnose the patient with atopic dermatitis.

Question 17.2.2 Which of the following is true about atopic dermatitis?

A) The prevalence of atopic dermatitis appears to be decreasing worldwide

B) Atopic dermatitis tends to worsen with use of emollients

C) In some patients, skin infections can exacerbate atopic dermatitis

D) Positive skin prick tests and RAST testing correlate highly with food challenges (e.g., those with positive tests will have worsening of their rash when given a food challenge)

E) In most infants, atopic dermatitis will not significantly improve or resolve by school age

Answer 17.2.2 The correct answer is "C." Skin infections (Staph or Strep infections) can be associated with worsening atopic dermatitis, and when children flare, impetiginization (superinfection) should be considered. In these situations, a course of antibiotics may improve the overall clinical course (cephalexin is often a good choice). Sixty percent of atopic dermatitis appears in the first year of life, usually after 2 months of age; and it will usually get somewhat better by school age. The cause of atopic dermatitis is not yet known. The role of specific allergens is controversial. In some patients, a food allergy can worsen the disease but is not thought to be the cause. However, in severe, unresponsive atopic dermatitis, food allergens should be evaluated. Most patients who have positive allergy testing to foods do not have improvement in their skin with removal of the allergen. Atopic dermatitis does tend to improve as the affected child ages ("E"), and the use of emollients ("B") is a cornerstone of therapy.

Question 17.2.3 The clinical features of impetiginized atopic dermatitis include:

A) Lichenification of the skin

B) Pruritus and relapsing nature

C) Associated asthma or allergic rhinitis

D) Elevated IgE serum levels

E) Redness of the skin with honey-crusting

Answer 17.2.3 The correct answer is "E." Although all of the above can be associated with atopic dermatitis, honey crusting implies a secondary bacterial infection (impetigo), which is common in atopic dermatitis and needs to be recognized and treated to get atopic dermatitis under control. Oral antibiotics and chlorinated baths can be used to help control the superinfection. Waxing and waning pruritus is what defines this common skin condition. Chronic scratching often leads to thickened skin with accentuation of skin lines (lichenification). Early lesions will not have lichenification, however. Asthma and allergic rhinitis can be associated with atopic dermatitis. This common hypersensitivity triad is referred to as atopy (although atopic dermatitis is not allergic in nature). "D," elevated IgE, does occur in patients with atopic dermatitis, and higher levels of serum IgE are associated with more extensive disease of greater chronicity. However, an elevated IgE level is merely an association and is not pathognomonic of atopic dermatitis. Erythema of the skin is a nonspecific sign of inflammation and is seen in many skin disorders.

Question 17.2.4 Your initial recommendation should include which of the following in the management of atopic dermatitis:

A) Daily use of thick emollients such as white petrolatum

B) Bathing with lukewarm water and mild cleansers

C) Topical corticosteroids or topical immunomodulators

D) Oral antibiotics if there is evidence of superinfection

E) All of the above

Answer 17.2.4 The correct answer is "E." The protective barrier of the skin is broken down in patients with atopic dermatitis. By frequently applying a protective barrier, such as petrolatum, the skin becomes less pruritic resulting in less itching-induced skin trauma and rash, thus decreasing the "itch-scratch cycle." This is the most important aspect of long-term management. Topical steroids and immunomodulators work well to decrease the inflammation in the skin and are first-line anti-inflammatory treatment; however, the goal is to protect the skin with thick emollients so that the skin does not dry out and itch, leading to scratching and subsequent inflammation. Daily bathing with mild cleansers and cool water followed by the application of emollients is recommended. Patients with atopic dermatitis have a higher bacterial count of Staphylococcus aureus on their skin. By bathing for short periods daily, the bacterial count is decreased, thus decreasing the risk of secondary infection. Oral antihistamines cause some level of sedation, which is often helpful at night when the child is awake and itching. Interestingly, there is almost no evidence to support the use of antihistamines in the treatment of atopic dermatitis, except small studies that have shown nonsedating antihistamines to be no better than placebo. If you choose to recommend an antihistamine, use an older drug (e.g., diphenhydramine) but use extreme caution in children under 2 years of age—there is no proven benefit for any indication in this age range and infants are more sensitive than adults and older children to the CNS depressant effects of diphenhydramine. "E" is incorrect. However, oral antibiotics may be necessary if there is extensive impetigo. Finally, bacteria can lead to a flare of atopic dermatitis. Occasionally, treatment with antibiotics may be of benefit (more below).

A recent ear infection has caused your patient's skin to worsen. He returns to clinic and your physical examination reveals the skin lesion seen in Figure 17-2. He has appreciably enlarged cervical lymph nodes. The patient has no known drug allergies.

FIGURE 17-2. (Courtesy of Drs. Karolyn Wanat and Megan Noe.)

Question 17.2.5 Which of the following oral antimicrobials would be the best initial choice for this patient?

A) Cephalexin

B) Ciprofloxacin

C) Metronidazole

D) Tetracycline

E) No systemic treatment is necessary at this time

Answer 17.2.5 The correct answer is "A." Patients with atopic dermatitis are prone to certain skin infections that may exacerbate their disease. Ninety percent of patients with atopic dermatitis will grow S. aureus on swab cultures of their crusted lesions. By decreasing the bacterial count, inflamed lesions often heal faster. Depending on your community susceptibilities, community-acquired methicillin-resistant S. aureus (CA-MRSA) may be of concern. However, first-generation cephalosporins are a reasonable initial antibiotic choice for impetiginized atopic dermatitis because of excellent skin penetration and activity against Gram-positive cocci (both Staph and Strep). Tetracycline is another option for impetiginization; however, this should be avoided in young children, as should fluoroquinolones (except in rare cases such as cystic fibrosis). Systemic therapy is necessary at this time due to clinical worsening and presence of lymphadenopathy.

Your patient's culture results are consistent with methicillin-sensitive S. aureus (MSSA). With the appropriate antibiotics, the patient improves markedly. Time to rest on your laurels … Wait … there's this little thing called continuity of care, and 3 months later, your patient returns with a new eruption. Clinical appearance is shown in Figure 17-3.

FIGURE 17-3.

Question 17.2.6 Which of the following is the most appropriate treatment at this time?

A) Acyclovir

B) Cephalexin

C) Ciprofloxacin

D) Metronidazole

E) A and B

Answer 17.2.6 The correct answer is "E." Patients with eczema may also develop eczema herpeticum, a particularly severe form of disseminated herpes simplex with punched out erosions and rapid spread of HSV within the areas of eczema. Patients can develop both eczema herpeticum and impetiginization, so treatment of both is important. The characteristic look of punched out erosions requires immediate therapy with acyclovir, and often requires intravenous medications. These patients should be treated immediately with antivirals as the disease may be fatal. Treatment with cephalexin in addition should be utilized, especially because the patient improved previously.

As the patient grows, he improves significantly. However, his skin continues to be sensitive to many products. As a teenager, he presents with a recurring rash near his wrist that is intensely pruritic. He has recently started wearing a bracelet … and he won't take it off despite the rash because he's too cool … even though it seems to be a girl's bracelet (see Fig. 17-4).

FIGURE 17-4.

Question 17.2.7 The test most likely to confirm your presumptive diagnosis is:

A) Potassium hydroxide (KOH) of a skin scraping

B) Tzanck preparation

C) Patch testing

D) Serum thyroid-stimulating hormone level

E) Serum IgE levels

Answer 17.2.7 The correct answer is "C." The patient most likely has an allergic contact dermatitis to the nickel in the metal bracelet on his wrist. Patients with a history of atopic dermatitis are more likely to have contact hypersensitivities. Nickel is a common contact allergen and can also be seen with contact to earrings, optical glasses, and buttons on jeans. Patch testing is a test for reactions to delayed-type hypersensitivity reactions that can identify many of the common contact allergens in the skin. KOH application to a skin scraping is used to identify fungal elements. KOH dissolves keratin, the protein in skin, to better identify the fungal elements. Tzanck preparations stain blister scrapings to evaluate lesions suspicious for herpes or varicella viruses. Thyroid disease can cause many skin conditions but is not a known cause of allergic contact dermatitis. An abnormality in the TSH level is least likely to yield a diagnosis in this case. As to "E," serum IgE levels may be elevated in atopic patients, but this is not diagnostic as IgE can be elevated in many states.

Objectives: Did you learn to…

• Recognize atopic dermatitis by its classic presentations?

• Identify the hallmarks of atopic dermatitis?

• Manage a patient with atopic dermatitis and its complications?

• Recognize that eczema herpeticum in those with atopic dermatitis?

A 49-year-old obese white male with poorly controlled diabetes mellitus, hypertension, and hyperlipidemia presents to clinic for a regularly scheduled visit. He complains that his left and right legs are extremely red and painful. He denies constitutional symptoms. His vital signs are within normal limits. He has warm legs with circumferential erythema extending from the ankle to the mid-calves with 2+ pitting edema bilaterally with hemosiderin staining (brownish macular lesions) of the ankles. There is no lymphadenopathy. There are no open sores or minor trauma noted (see Fig. 17-5). His complete blood count with differential is within normal limits. You send him for Doppler studies that fail to reveal venous thromboses. You prescribe 7 days of oral antibiotics and send him home, confident that your therapy will not fail.

FIGURE 17-5.

He returns 3 days later with modest improvement in the redness. After completing the antibiotic course, he presents to clinic 3 weeks later complaining of return of the redness. (Why don't patients just get better with a pill like they are supposed to?)

Question 17.3.1 The most appropriate next step in the care of this patient is to:

A) Prescribe another course of oral antibiotics for 14 days

B) Admit the patient to the hospital for intravenous antibiotics

C) Send a punch biopsy of skin for bacterial culture

D) Recommend daily leg elevation and use of compression hose

E) Prescribe a diuretic (e.g., furosemide)

Answer 17.3.1 The correct answer is "D." This patient has a characteristic history of stasis dermatitis, a condition that is often misdiagnosed as recurrent or chronic cellulitis. Stasis dermatitis is a dermatitis of the lower extremities that results from chronic edema. It can start relatively abruptly and be unilateral or bilateral. The pitting edema with hemosiderin staining is a clue that there is chronic fluid extravasation from the vessels of the lower extremities. Ectatic veins may also be present. The goal of therapy is directed at resolution of the edema. Patients must lose weight and employ a strict routine of compression hose and leg elevation. In the short term, topical corticosteroids can improve the inflammation. In general, diuretics should not be used simply to treat edema, as these drugs have numerous systemic effects. Paradoxically, diuretics can actually make edema worse in the long term by causing low circulating volume and renal retention of sodium and water to make up for the diuretic-induced hypovolemia. Chronic lower extremity edema can lead to local tissue necrosis, resulting in ulceration. With long-standing venous insufficiency, more chronic changes can also occur including lipodermatosclerosis (which is "woody" fibrosis), bound down skin as well as overlying retention of the skin and verrucous features (elephantiasis nostra verrucosum).

From years of diabetic nephropathy, the patient's kidneys eventually fail leading to transplantation (and use of immunosuppressants). After 5 years of stable renal function and improved control of his diabetes, he develops a new nonhealing lesion on the left forearm.

Question 17.3.2 What cutaneous malignancy is he at the highest risk of developing?

A) Basal cell carcinoma

B) Malignant melanoma

C) Squamous cell carcinoma

D) Metastases from an undiagnosed internal malignancy

E) Kaposi sarcoma

Answer 17.3.2 The correct answer is "C." All primary cutaneous malignancies are increased in immunosuppressed patients. However, squamous cell carcinoma is the most common in transplanted, immunosuppressed patients, surpassing basal cell carcinoma, which is most common in the general population. Depending on sun exposure and length of immunosuppression, the incidence of squamous cell carcinoma in transplant populations is as high as 45%. Any nonhealing lesion should be further investigated with a biopsy. There are also significantly increased rates of Kaposi sarcoma in immunocompromised patients.

You removed the lesion, which was indeed squamous cell carcinoma. Good job! The patient develops a shallow ulcer superior to the medial malleolus. "Is that another one of them cancers, Doc?" your patient asks.

Question 17.3.3 The most common cause of an ulceration at this location is

A) Arterial insufficiency

B) Diabetic neuropathy

C) Chronic venous stasis

D) Pyoderma gangrenosum

E) Prolonged pressure (e.g., "decubitus" ulcer)

Answer 17.3.3 The correct answer is "C." Your patient is at risk for many of the above diagnoses; however, venous ulcerations classically occur over the medial lower leg. In contrast to this patient's venous ulceration, arterial insufficiency ulcers ("A") classically have a punched-out appearance and occur over bony prominences (e.g., malleoli) or distal aspects (e.g., tips of toes) and are extremely painful (in the absence of neuropathy) and usually dry. Poor peripheral pulses, cool extremities, and hairlessness are clues to arterial insufficiency. Abnormal ankle–brachial indices help to confirm peripheral artery disease. Neuropathic ulcers ("B"), such as those associated with diabetic neuropathy, also occur over pressure points including the plantar surface of the foot. The patient may complain of burning or tingling of the foot, but the ulcer is asymptomatic (because of lack of pain sensation from diabetic neuropathy). Pyoderma gangrenosum ("D") is a rare cause of ulceration associated with systemic diseases including inflammatory bowel disease, connective tissue diseases, and hematologic malignancies. Pressure ulceration ("E") is common and results from tissue ischemia from prolonged pressure, usually over bony prominences, such as the sacrum, coccyx, and heels.

As you start to exit the examination room, the patient states "Oh by the way, Doc, can you do anything for my toenails?" Your examination reveals three, yellow heaped-up nails on the left foot. You suspect a dermatophyte infection.

Question 17.3.4 What do you do next?

A) Perform a KOH examination of toenail scrapings

B) Empirically treat with an oral antifungal

C) Empirically treat with a topical antifungal

D) Tell the patient that his nails are the least of his worries

Answer 17.3.4 The correct answer is "A." The cost of antifungal therapy has declined substantially over the last few years with generic options becoming available. Some experts now argue that "B," empiric therapy, is reasonable in otherwise healthy patients without contraindications. However, a board examination is not real life, and "A" would be the best choice. Here's the argument for testing prior to treating: all that looks fungal is not necessarily fungal. Dystrophic nails can mimic onychomycosis and may be the result of psoriasis, eczema, trauma, or other inflammatory conditions. KOH is an inexpensive and easy test to perform in the clinic setting. If it is negative, then a toenail clipping can be sent for fungal culture or pathologic study with periodic acid–Schiff staining if desired.

The KOH is negative, so you send a toenail clipping for culture. It grows a Candida species.

Question 17.3.5 Which of the following would be the LEAST efficacious medication?

A) Amphotericin

B) Fluconazole

C) Nystatin

D) Terbinafine

E) Voriconazole

Answer 17.3.5 The correct answer is "D." All the above medications have some Candida species coverage, but terbinafine (Lamisil) has the least yeast coverage. Of note, amphotericin would be the most toxic (but still would work well) and should be avoided. A plea from your editors: the topical "paint on" nail antifungals are relatively expensive, have a marginal benefit, and the recurrence rate tends to be high. Besides, who is really going to paint their nails everyday for a year?

Another patient comes in with toenail fungus, but this time he has white changes, most prominent on his proximal nailfolds.

Question 17.3.6 You would like to test him for:

A) Diabetes mellitus

B) Kidney disease

C) Lupus erythematosus

D) HIV

E) Yum, let's go eat mushrooms

Answer 17.3.6 The correct answer is "D." This pattern of dermatophyte infection, proximal white subungual onychomycosis, is characteristic of immunosuppression and particularly HIV disease. Testing for underlying HIV is important with this clinical presentation. Other nailbed changes can be seen with diabetes, kidney disease, and lupus. As to "E," mushrooms might have this appearance but don't grow on toes—we hope. As an aside, there is a great restaurant in Jogjakarta, Indonesia, where everything is made out of various types of mushrooms (shelf fungus, etc.). It is pretty yummy. If you are in the area check out "Je Jamuran."

Objectives: Did you learn to…

• Recognize the presentation of stasis dermatitis and describe its etiology?

• Treat stasis dermatitis?

• Recognize the cutaneous malignancies seen in transplanted, immunosuppressed patients?

• Differentiate between common causes and sites of lower extremity ulcerations?

• Diagnose and treat onychomycosis?

You are working in the student health clinic at the local university when a previously healthy 19-year-old female presents with malaise for 3 weeks and a severe sore throat for 3 days. Yesterday, she took some old amoxicillin that her roommate gave her. Today, she developed a diffuse macular, red skin eruption, starting on her chest and spreading to involve her extremities. Her mucous membranes, palms, and soles are free of lesions, but she has enlarged tonsils with exudates and large cervical lymph nodes, including prominent posterior nodes. A rapid Strep test is negative.

Question 17.4.1 You suspect:

A) An allergic reaction to the amoxicillin

B) An Epstein–Barr virus infection (mononucleosis)

C) An enterovirus infection

D) A gonococcal infection

E) Scarlet fever

Answer 17.4.1 The correct answer is "B." All of the above infections except for enterovirus can present with an exudative pharyngitis; enterovirus presents with gastrointestinal or meningeal symptoms. The clinical scenario describes the usual course of infectious mononucleosis: a college-age student, a few week prodrome of malaise, and posterior cervical lymphadenopathy. Amoxicillin or ampicillin given to patients with infectious mononucleosis can result in a macular, diffuse rash. This is not an allergy but can be mistaken for one. Scarlet fever, which this patient does not have, is a complication of group A streptococcal infection, which presents with an erythematous, coarse ("sandpaper") rash, strawberry tongue, and skin desquamation.

Later that same day, a 16-year-old male presents with a mildly pruritic rash on his trunk. He had a cold few weeks earlier but is otherwise healthy. He denies high-risk sexual activity or IV drug abuse (of course, your definition of "high-risk" and his may not be the same!). Your examination reveals the findings in Figure 17-6.

FIGURE 17-6. (Courtesy of Drs. Karolyn Wanat and Megan Noe.)

Question 17.4.2 You tell the patient:

A) This skin condition is usually chronic and relapsing

B) That topical corticosteroids are needed to speed up the healing

C) That the rash usually resolves within 6 to 8 weeks without treatment

D) That the rash is likely to be fatal

E) That he is living a Kafkaesque nightmare and slowly metamorphosing into an insect

Answer 17.4.2 The correct answer is "C." The rash is consistent with pityriasis rosea (PR), which is an acute, often asymptomatic, eruption on the trunk and proximal extremities. The etiology is (still) unknown. Secondary syphilis, which is on the rise in some areas of the United States, can mimic PR. A sexual history is necessary, and appropriate laboratory studies should be undertaken if a patient is sexually active, especially if high-risk behaviors have occurred or if local syphilis rates are high. PR, unlike syphilis, often resolves within 8 weeks without treatment and does not usually recur. Topical steroids are not necessary for healing but may be helpful in the minority of patients who experience itching. "E" is incorrect. This rash just isn't that serious.

Your next patient is a 20-year-old female complaining of "a rash down there." You confirm that she is talking about a vulvar rash and ask about her sexual history. She says that she had not been sexually active with anyone for about 1 year until a recent spring break fling in Florida. On examination, you find a rash over the pubic region and extending into the inguinal areas and medial thighs. There is no pain or pruritus (see Fig. 17-7).

FIGURE 17-7.

Question 17.4.3 Which of the following is FALSE?

A) These lesions are transmitted in adults only by sexual contact

B) If not treated, the lesions may resolve on their own

C) Topical corticosteroids do not improve this skin condition

D) The lesions are contagious and can spread readily and rapidly

E) The skin lesions are a result of a viral infection

Answer 17.4.3 The correct answer is "A." These lesions, referred to as molluscum contagiosum, result from a pox virus. Molluscum is commonly spread via sexual contact in adults; however, any physical human contact can also spread it. Molluscum is extremely common in children in daycare settings. The lesions generally resolve in time without treatment. Because they can be auto-inoculated, the molluscum lesions can rapidly increase in number, and it is for this reason that treatment is recommended. Treatment consists of destructive methods, such as cryotherapy or curetting. The immune modulator imiquimod has been used, but is not approved by the Food and Drug Administration (FDA) for molluscum, and only small trials have been undertaken. Topical steroids are not indicated. In immunocompromised patients, molluscum lesions can be widespread and persist much longer.

Your next patient is a healthy 18-year-old male who presents for treatment of plantar warts. He has tried topical salicylic acid 17% at home. He used it for a few weeks without significant improvement.

Question 17.4.4 Which of the following can be used for therapy for plantar warts (verruca plantaris)?

A) Cryotherapy (liquid nitrogen)

B) Duct tape occlusion

C) Imiquimod

D) Candida antigen injection

E) All of the above

Answer 17.4.4 The correct answer is "E." No therapy for cutaneous warts (plantar or otherwise) has been proven superior, and all of the options can be used with different pros and cons. "A," cryotherapy, is easily performed in the office and is quick but may be too painful for children to tolerate. Also, cryotherapy may result in hypopigmented scarring in dark-skinned patients. As we all know, duct tape can be used for anything (e.g., holding your muffler together, preventing poison gas exposure) and has been used to treat warts, but the evidence is conflicting. "C," imiquimod, is initially painless, can lead to a brisk inflammatory response, and unlikely to cause scarring, so it is a good choice for facial warts or dark-skinned patients. However, it is the most expensive option. "D," candida antigen injection, is a therapy that aims at stimulating an immune response to the warts. Mumps antigen has been used as well. In the antigen injection studies, only one wart was injected to achieve treatment for all of a patient's warts. This can be effective but is a painful injection. Destructive methods are all approximately 70% effective at eradicating warts. It is important to remind patients that no single method is more likely to work than another, and warts can resolve on their own. In immunocompetent patients, most warts resolve in time without treatment. For young children, this is an important issue, since they cannot understand the pain associated with most treatment modalities.

A 30-year-old stressed out medical student presents to your clinic with a worsening, painful rash on one side of her chest. She denies any prior spots like this and has no other medical problems. She is up-to-date on her vaccinations because of medical school and complains that this rash is interfering with studying for the upcoming final block of examinations (she wants to be a dermatologist, so she really has to ace her examinations). Physical examination demonstrates a linear group of vesicles with erythema on her left chest.

Question 17.4.5 Treatment should be initiated with which of the following therapies:

A) Cephalexin

B) Mupirocin

C) Paroxetine

D) Valacyclovir

E) No treatment is necessary as this is self-limited

Answer 17.4.5 The correct answer is "D." This is most likely herpes zoster, which is reactivation of the varicella zoster virus. Valacyclovir is an effective treatment. Even in immunocompetent patients, herpes zoster can be reactivated from the dorsal root ganglion during periods of stress. Although it can be self-limited, treatment with antiviral (valacyclovir or acyclovir) is recommended during first 72 hours to decrease outbreak and risk of postherpetic neuralgia. With the presentation of pain, gabapentin or pregabalin is also often prescribed.

Objectives: Did you learn to…

• Recognize that ampicillin/amoxicillin given to patients with mononucleosis will often result in a macular rash?

• Diagnose pityriasis rosea (PR) and recognize secondary syphilis as a mimic?

• Recognize and treat molluscum contagiosum?

• Describe the treatment modalities for verruca plantaris?

• Recognize and treat herpes zoster?

Which of the following represents a type IV hypersensitivity reaction?

A) Serum sickness reaction

B) Contact dermatitis to poison ivy

C) Urticaria

D) Vasculitis

The correct answer is "B." Contact dermatitis has a geometric appearance and a characteristic immune-mediated reaction; someone may not react when they first encounter the agent and then develop stronger inflammatory responses with subsequent exposures. Contact dermatitis is an example of a delayed-type hypersensitivity reaction. Serum sickness is a type III immune complex reaction. Urticaria is a type I hypersensitivity response, mediated by mast cell degranulation. Vasculitis can be either immune complex, antibody, or complement mediated.

You are rounding in the newborn nursery. A healthy 2-day-old term infant has a new rash characterized by yellow pustules on an erythematous base (Fig. 17-8) involving the trunk and extremities but sparing the palms and soles.

FIGURE 17-8.

Question 17.5.1 What is the diagnosis?

A) Transient neonatal pustular melanosis

B) Herpes simplex

C) Miliaria

D) Erythema toxicum neonatorum

E) Epidermolysis bullosa

Answer 17.5.1 The correct answer is "D." Erythema toxicum neonatorum is a common, benign, self-limited rash seen in term infants. Lesions usually appear after 24 to 48 hours of age. Lesions may begin as erythematous macules that progress to yellow pustules on an erythematous base, may be sparse or numerous, and involve the trunk and extremities, sparing the palms and soles. The etiology is unknown and the diagnosis is clinical. Transient neonatal pustular melanosis ("A") usually affects term African-American infants presenting at birth with pustules on a hyperpigmented macule that may involve the palms and soles. Neonatal herpes ("B") presents with blisters or erosions and an ill-appearing child. Diagnosis is made via a Tzanck preparation demonstrating multinucleated giant cells, viral culture, or direct fluorescent antibody for HSV 1 or 2. Commonly seen in warm climates, miliaria ("C") or "prickly heat" is due to blocked sweat ducts presenting as noninflamed pinpoint clear diffuse vesicles. Epidermolysis bullosa ("E") is a chronic blistering disease presenting as blisters at sites of mild trauma.

While taking care of the neonate in the newborn nursery, you notice a child in isolation. His skin catches your eye (see Fig. 17-9).

FIGURE 17-9.

Question 17.5.2 The most common cause of this rash in newborns in the United States is:

A) Cytomegalovirus (CMV)

B) Rubella

C) Langerhans cell histiocytosis

D) Rh incompatibility

E) Parvovirus B19

Answer 17.5.2 The correct answer is "A." All the above can present as a "blueberry muffin baby"; however, CMV is the most common cause in the United States. CMV is the most common congenital viral infection, affecting about 1% to 2% of all births. Rubella was the most common cause in the prevaccination era. In most cases, the purple plaques represent extramedullary hematopoiesis.

Later that same morning, a previously healthy 2-month-old neonate presents to your clinic with peeling of the skin and a fever (Fig. 17-10). She had appeared well until 2 days ago when she became more irritable. Her mother noted a decrease in her urine output. The child was born vaginally without complications and has no known medical conditions. On physical examination, you notice a well-nourished, crying infant with large sheets of desquamating skin on her extremities. Her mucus membranes appear normal. You order complete blood count and urine analysis.

FIGURE 17-10. (Courtesy of Drs. Karolyn Wanat and Megan Noe.)

Question 17.5.3 The most likely diagnosis is:

A) Toxic epidermal necrolysis (TEN)

B) Burns

C) Staphylococcal scalded skin syndrome (SSSS)

D) Diffuse cutaneous mastocytosis

Answer 17.5.3 The correct answer is "C." This is Staphylococcal scaled skin syndrome, which results from a distant Staphylococcal infection (often involving urinary tract, nasopharynx, eyes, perianal areas). The key features of SSSS in Figure 2-10 are bright red erythema with impending desquamation in the neck folds and periorificial areas with sparing of the oral mucosa. So what differentiates "C" from "A?" TEN presents with shedding of sheets of skin and often has mucosal involvement that separates it clinically from SSSS. Both can present with significant skin pain. However, TEN is a result of drug hypersensitivity or bacterial sepsis (in the case of the neonate children); and neonates with TEN are quite ill compared with children with SSSS. In TEN, a biopsy would show full-thickness necrosis of the epidermis versus an intraepidermal split in SSSS. Burns ("B") can mimic SSSS, but burns would not be likely to cause a diffuse red eruption and will often have a specific shape depending on what burned the skin. "D," diffuse cutaneous mastocytosis, can present with hemorrhagic blisters and erosions, but these are usually focal areas, not sheets of skin loss. Keep reading for more information on SSSS.

Question 17.5.4 In this case of SSSS, peeling of the skin is a result of:

A) Necrosis of the entire epidermis from lymphocyte attack

B) A widespread bacterial skin infection

C) Histamine released in the skin with edema and blistering

D) Toxin-mediated skin blistering from nonskin source of infection

Answer 17.5.4 The correct answer is "D." This clinical scenario describes SSSS, which is an epidermolytic toxin-driven disease. Extreme tenderness of the skin precedes superficial, widespread desquamation. The skin is usually bright red with areas of flakiness. Radial wrinkling of the mouth, giving an "old, sad man" appearance, is common. The source of infection is not the skin but rather an occult site such as nasopharynx, eye, perianal area or urinary tract; therefore, investigation for a causative infection should be undertaken (e.g., blood, nares, ocular, perianal, and urine cultures).

Objectives: Did you learn to…

• Recognize neonatal benign cutaneous eruptions?

• Identify a "blueberry muffin" neonate and know the common causes?

• Recognize SSSS and consider its differential diagnosis?

Which of the following nail findings–systemic disease pairing is INCORRECT?

A) Muehrcke nails–nephrotic syndrome

B) Nail pitting–psoriasis

C) Periungual fibroma–tuberous sclerosis

D) Splinter hemorrhages–infective endocarditis

E) Koilonychia–systemic lupus erythematosus

The correct answer is "E." Koilonychia, otherwise known as "spoon nail," is a result of softening and thinning of the nail plate and is found in patients with long-standing iron deficiency anemia, Plumer–Vinson syndrome, Raynaud disease, hemochromatosis, and trauma. It can also be inherited as an autosomal-dominant trait. Connective tissues diseases, such as lupus, are more commonly characterized by nail fold abnormalities, such as nail fold telangiectasias, rather than koilonychia. Muehrcke nails ("A") have paired narrow horizontal (meaning perpendicular to the long axis of the finger) white bands, separated by normal nail, which remain static as the nail grows. They are most often seen in patients with nephrotic syndrome, and their presence reflects the degree of hypoalbuminemia. When you see onycholysis (separation of the nail plate from the nail bed that appears opaque), consider trauma, onychomycosis, psoriasis, and other systemic disease. Nail pitting can be associated with several conditions including psoriasis, atopic dermatitis, and alopecia areata. A periungual fibroma ("C") should prompt evaluation for tuberous sclerosis with brain imaging for tuberous lesions. Splinter hemorrhages ("D") are usually a result of trauma but can be a sign of infectious endocarditis.

A 52-year-old white male presents to clinic with a nonhealing, asymptomatic "pimple" on the cheek. It has been present for 6 months and has recently started to bleed when he shaves. On examination, you note his fair skin, blue eyes, and ruddy complexion. You find the lesion in Figure 17-11.

FIGURE 17-11.

Your preliminary diagnosis is:

A) Sebaceous hyperplasia

B) Squamous cell carcinoma

C) Basal cell carcinoma

D) Metastases from internal malignancy

E) Merkel cell carcinoma

The correct answer is "C." The photograph is a classic picture of a basal cell carcinoma with its rolled, pearly pink borders, and telangiectasias. It is found commonly on sites that get a lot of sun exposure, especially the head and neck. People with fair skin and light hair and eyes are at particular risk. Sebaceous hyperplasia can look similar but is ivory or yellow in appearance and has lobulated appearance with a central pore. Squamous cell carcinoma is usually a hyperkeratotic or ulcerated papule or plaque. Metastases from solid organ malignancies are subcutaneous, firm nodules, although they may ulcerate. Merkel cell carcinoma is a rare tumor on the head and neck that usually appears as an ill-defined, violaceous nodule.

While working in the emergency department, a 6-month-old healthy female infant is brought in by her grandmother. She is bleeding from her birthmark on her buttocks (see Fig. 17-12). Her grandmother watches her during the day while her mother is at work and has noticed the lesion getting larger recently. After holding pressure on the lesion for about 20 minutes, the bleeding stops. You educate the grandmother about the natural history of the "birthmark."

FIGURE 17-12.

Question 17.6.1 Which of the following is NOT a true statement about this type of birthmark?

A) This is the most common type of soft-tissue tumor of infancy

B) Most of these birthmarks undergo spontaneous involution

C) Treatment is indicated in all lesions lest they become malignant

D) β-Blockers are the most appropriate therapy for ulcerated lesions

E) Many are not present at birth but develop shortly thereafter

Answer 17.6.1 The correct answer is "C." The child has an ulcerated hemangioma of infancy. Infantile hemangiomas are benign proliferations of endothelial cell lineage that are usually present at birth or soon thereafter. They are characterized by rapid growth in the first several months of life with a plateau occurring around 1 year of age. They spontaneously involute over years. Treatment options should be individually tailored, depending on the size and location of the lesion. Lesions located on the central face or in the diaper area should be treated, as should ulcerated hemangiomas at any body site. Topical or oral β-blockers are the standard of care for infantile hemangiomas that require treatment. Larger, segmental hemangiomas should be further evaluated with imaging studies to rule out syndromes with other associated anomalies such as PHACES syndrome (posterior fossa malformation, hemangioma, arterial anomalies, cardiac defects, coarctation of the aorta, eye abnormalities, sternal defects/supraumbilical raphe) and LUMBAR syndrome (lower body hemangioma, urogenital anomalies, myelopathy, bony deformities, anorectal malformation/arterial anomalies, and renal anomalies).

The same patient returns, this time with mom, at age 5. The hemangioma has involuted. About 2 months ago, the mother noticed a spot on the patient's left index finger, and now she is concerned that it is not resolving. The patient is not bothered by the lesion, except that it occasionally bleeds when she bumps it on something. On examination, you find a 3-mm dome-shaped, bright red nodule on the palmar aspect of the left index finger. It is nontender and smooth (see Fig. 17-13).

FIGURE 17-13.

Question 17.6.2 The most likely diagnosis is:

A) Basal cell carcinoma

B) Squamous cell carcinoma

C) Acne

D) Pyogenic granuloma

E) Nodular melanoma

Answer 17.6.2 The correct answer is "D." This patient most likely has a pyogenic granuloma, which is essentially a nodular hemangioma arising at sites of trauma, especially the fingers and toes. Although pyogenic granuloma is not cancerous, it can be confused with basal and squamous cell carcinomas as well as melanoma. For this reason, it is prudent to perform excision and histologic examination. After excision, the base of the lesion should be ablated (electrocautery or laser), or the pyogenic granuloma may return. Pyogenic granulomas are more common during pregnancy and have been associated with drugs such as oral retinoids, indivair, EGFR inhibitors, methotrexate, sirolimus, and capecitabine. "C," acne, should not be a consideration, as sebaceous glands are not found on the palms. By the way, did you notice that this poor child has developed coarse, dark hair growth on her knuckles? As it turns out, she's been playing with dad's Rogaine.

Objectives: Did you learn to…

• Describe the natural history of infantile hemangiomas?

• Identify options for treating ulcerated hemangiomas?

• Describe the features and management of pyogenic granuloma?

A 78-year-old female presents with a rash on her legs. It started 1 week ago and was preceded by itching of the legs without any visible changes. Then red blotches developed that quickly became blisters. She denies pain or drainage. She also has some sores in her mouth. She reports overall good health and takes no medications. On examination, you find an afebrile, comfortable looking female. She has 1+ pitting edema at her ankles. You notice round, tense bullae erupting on erythematous patches on the abdomen and extremities. There are also scattered erosions present at the sites of previous bullae. The bullae contain clear fluid. There is no purulent material or blood (see Fig. 17-14).

FIGURE 17-14. (Courtesy of Drs. Karolyn Wanat and Megan Noe.)

Question 17.7.1 Which of the following is the most likely diagnosis?

A) Pemphigus vulgaris

B) Bullous pemphigoid

C) Varicella zoster

D) Dermatitis herpetiformis

E) Stevens–Johnson syndrome (SJS)

Answer 17.7.1 The correct answer is "B." Bullous pemphigoid is an autoimmune disorder and is primarily a disease of the elderly. Often patients will report pruritus or urticaria-like lesions, prior to the eruption of typical bullous lesions. When the bullae form, they are frequently asymptomatic but can be intensely pruritic and/or mildly tender. In contrast to pemphigus vulgaris ("A") and SJS ("E"), systemic symptoms are not part of bullous pemphigoid. Additionally, pemphigus vulgaris lesions are painful, and classically the bullae are flaccid rather than tense. SJS generally occurs in response to medications, and this patient is taking none. Varicella zoster ("C") should follow a dermatomal pattern rather than appear bilaterally; zoster is usually associated with pain and paresthesia. Dermatitis herpetiformis ("D") presents with crops of vesicles and excoriations rather than bullae.

Although she feels well, the lesions are dramatic, and the patient is very concerned that she might have cancer. To confirm your diagnosis, you decide to biopsy the skin.

Question 17.7.2 The most appropriate way to perform a biopsy in this situation is:

A) 4-mm punch biopsy of the margin of an intact bulla for light microscopy

B) 4-mm punch biopsy of perilesional normal skin for light microscopy

C) 4-mm punch biopsy of perilesional normal skin for immunofluorescence

D) A and B

E) A and C

Answer 17.7.2 The correct answer is "E." Bullous pemphigoid is diagnosed definitively by demonstration of autoantibodies deposited along the basement membrane of normal skin. Immunofluorescence examination of normal-appearing skin can demonstrate linear depositions of IgG and C3. A biopsy of the edge of an intact bulla will show the characteristic pathology of a subepidermal blister with eosinophils. For a definitive diagnosis, both "A" and "C" should be done.

You assure her that the lesions are not cancerous.

Question 17.7.3 What else can you tell her about the prognosis of bullous pemphigoid?

A) The average course resolves spontaneously in 5 to 6 years

B) It is associated with an increased risk of systemic malignancy

C) It is associated with a high mortality rate

D) It will likely spread to cover her entire body until she's one big blister, and her hair will fall out, and her friends will shun her, a la Job in the Old Testament

Answer 17.7.3 The correct answer is "A." Bullous pemphigoid may undergo complete resolution and never recur. Alternatively, the disease may have resolutions and exacerbations over time. It is not associated with an increased risk of cancer or a high mortality rate. Very extensive involvement may lead to skin infections and bacteremia, but diffuse disease is not common.

She seems miserable. You want to offer her the medication with the fastest onset of action.

Question 17.7.4 What is the most appropriate treatment option with a fast onset of action?

A) Oral azathioprine

B) Oral cephalexin

C) Oral prednisone

D) Topical antimicrobials

Answer 17.7.4 The correct answer is "C." Bullous pemphigoid is an autoimmune disease, so anti-inflammatory medications and immunosuppressive agents are used to treat it. Oral steroids are the first-line treatment because of the quick onset of action; however because of concerns for long-term side effects patients should be transitioned to "steroid-sparing" agents as necessary. Once the disease is under control, oral steroids should be tapered to the lowest effect dose in combination with a tetracycline antibiotic or other immunosuppressive agent such as azathioprine, methotrexate, or mycophenolate. For patients with limited disease, high-potency topical steroids can also be used. Topical antimicrobials are used when treating infected, open bullae but are not effective for the treatment of the disease itself.

Objectives: Did you learn to…

• Distinguish bullous diseases from one another?

• Diagnose and treat bullous pemphigoid?

A 30-year-old female presents with a several month history of bumps on her chin and around her mouth. Although she has never had problems with acne, she thought that she was developing acne and tried benzoyl peroxide. A month ago, she stopped the benzoyl peroxide because it did not seem to work, and she switched to hydrocortisone cream, which has worsened the outbreak. The rash is neither itchy nor painful. She works in an office and cannot recall any contact irritants. On examination, you find erythematous papules with small pustules on the chin and laterally around her mouth (see Fig. 17-15). The neck and the remainder of the face are not involved.

FIGURE 17-15.

Which of the following treatments do you recommend?

A) Oral tetracycline

B) Oral isotretinoin

C) Topical high-potency steroids

D) Topical triple antibiotic ointment

E) Topical retinoic acid

The correct answer is "A." This patient appears to have perioral dermatitis. Appropriate treatments for perioral dermatitis include topical metronidazole or topical erythromycin or oral tetracycline antibiotics (tetracycline, minocycline, or doxycycline). The etiology of perioral dermatitis is unknown. "B" and "E" are incorrect, since these are treatments of acne vulgaris. "C" is incorrect, since high-potency topical steroids can make the condition worse, with rebound erythema upon discontinuation. Topical triple antibiotic ointment ("D") is not likely to be effective.

A 15-year-old male presents to your office complaining of "zits" on his face and back. He has several scattered comedones on his face and several deep nodules on his back. He also has some papulopustular lesions on his chin. You diagnose him with acne vulgaris.

Question 17.8.1 Which of the following is NOT TRUE about acne?

A) Noncomedonal acne is an inflammatory process

B) It commonly presents first in adolescence

C) It may first appear in adulthood

D) It is more severe in females than in males

E) The incidence is lower in Asians and Africans than in Caucasians

Answer 17.8.1 The correct answer is "D." Acne is an inflammatory process that involves the pilosebaceous units of the face and trunk. It can be comedonal, papulopustular, or nodulocystic in presentation. It typically presents first in adolescence with girls developing it from age 10 to 17 years and boys from 14 to 19 years. However, it may not appear until early adulthood. It is more severe in males than in females (thus "D" is not true), and it is less prevalent among Asians and Africans.

Your patient has heard many things about acne and wonders if they are true.

Question 17.8.2 Regarding acne, all of the following are true EXCEPT:

A) Acne is not caused by medications

B) Acne can be caused by industrial exposures such as cutting oils, aromatic hydrocarbons, and petroleum-based products

C) Infrequent facial cleansing does not cause acne

D) Emotional stress affects the course of acne

E) Acne can present at any age

Answer 17.8.2 The correct answer is "A." Acne can be caused by many medications including oral steroids, EGFR inhibitors, lithium, isoniazid (INH), and phenytoin. Medication-induced acne presents as monomorphic papules on the face, chest, and back. Exposure to industrial chemicals that occlude the follicle can also lead to an acneiform eruption. Neither infrequent washing nor chocolate (or any other foods) cause acne—no matter what your mother told you. However, stress (like that homecoming dance in high-school) can often flare acne.

There are different types of acne that can affect individuals at various stages of life. Neonatal acne presents shortly after birth and is transient. Infantile acne presents at 6 to 12 months of age and resolves within 1 to 2 years. The most common time to develop acne is around puberty; however, women in their 30s and 40s can also experience acne flares with hormonal fluctuations. As an aside, oral contraceptives (OCPs) go both ways with regard to acne: several OCPs are marketed to treat acne, but they have been reported to worsen acne in some patients. The result of OCPs may depend on the hormonal milieu of the specific patient (women with hyperandrogenism may benefit) and the type of progestin in the OCP. Acne is often improved in the summer months and worse in the fall and winter. Many women also tend to flare up right before menses.

Question 17.8.3 For acne, which of the following treatment principles is correct?

A) Treatment can often lead to initial worsening of lesions

B) Therapeutic response often takes several months

C) Mild acne can be treated with topical medications

D) Often times, two or more therapeutic agents must be combined for effective treatment

E) All of the above are correct

Answer 17.8.3 The correct answer is "E." Topical retinoids, topical antibiotics, and benzoyl peroxide are the first-line agents and can be titrated as needed. Retinoids should be applied at bedtime. The main oral antibiotic agents are tetracyclines and should be used as add-on therapy to topical agents for moderate-to-severe inflammatory acne. OCPs with low androgenic progesterones can also be helpful. Since acne lesions may take up to 2 months to resolve, one may not notice a therapeutic response for several months (once the current crop of lesions resolve).

After a few months of topical benzoyl peroxide wash and topical clindamycin cream, you add topical retinoic acid. Your patient returns with persistent lesions, including mild scarring and cystic lesions. You are considering referral for isotretinoin, which is indicated for severe, recalcitrant, nodular acne.

Question 17.8.4 Which of the following is FALSE regarding the use of isotretinoin?

A) Two methods of contraception are required in all reproductive age women along with frequent pregnancy tests

B) It should not be used with tetracycline

C) Hypertriglyceridemia is a possible side effect

D) Patient should be monitored closely for changes in mood

E) A patient can only receive one course of isotretinoin

Answer 17.8.4 The correct answer is "E." Isotretinoin is an oral retinoid and is pregnancy category X. Because of this, the FDA has developed a mandatory patient registry called "iPLEDGE." All patients must enroll in his registry before receiving the medication and prescribers also need to be registered. Female patients of reproductive age are required to use two contraceptive methods and have monthly pregnancy tests. As both tetracycline and isotretinoin can lead to pseudotumor cerebri, they should not be used together. Hypertriglyceridemia, dry skin, and decreased night vision are common side effects. There have been reports in the popular press and the scientific literature of suicide in patients on isotretinoin, though there is no good controlled data to suggest that the drug is responsible. Patients with a history of mental health issues should be followed carefully for any changes in their mood or behavior. Approximately one-third of patients who receive isotretinoin will require additional courses during their lifetime. Isotretinoin has been reported to cause premature closure of growth plates rarely.

Objectives: Did you learn to…

• Diagnose and treat acne?

• Identify side effects of isotretinoin?

A 26-year-old female patient presents to your office with painful, nonpruritic pink bumps that started last week on her shins. You find the firm lesions easier to palpate than to visualize (see Fig. 17-16).

FIGURE 17-16.

Question 17.9.1 What is the most likely diagnosis in this patient?

A) Erythema multiforme

B) Urticaria

C) Erythema nodosum

D) Erythema migrans

E) Lumpy shin disease (aka, "footballer's disease" in England)

Answer 17.9.1 The correct answer is "C." This is erythema nodosum. Typically, these firm nodules occur first on shins and are often more easily palpated than seen. They may then spread to the thighs, trunk, and extensor surfaces of the arms. Erythema multiforme ("A") presents as erythematous, targetoid lesions usually affecting the distal extremities including palms and soles. Urticaria ("B") is not tender but would be intensely pruritic. Erythema migrans ("D") is the quintessential lesion of Lyme disease: a nontender, nonpruritic red plaque with a central clearing. While "E" is technically correct in its description, we know of no such disease entity.

Question 17.9.2 Which of the following can cause erythema nodosum?

A) OCPs

B) Streptococcal pharyngitis

C) Sarcoid

D) Viral upper respiratory infection

E) All of the above

Answer 17.9.2 The correct answer is "E." All of these entities may cause erythema nodosum, but viral URI and streptococcal pharyngitis are most common. Multiple medications can also be responsible.

This patient does relate a history of URI symptoms about 1 week prior to the onset of her symptoms.

Question 17.9.3 What advice are you going to give this patient?

A) The rash tends to be self-limiting and will resolve in 4 to 6 weeks

B) The rash will heal with scarring

C) The rash will likely spread to the face and upper extremities before it resolves

D) This is a chronic disease and no treatment is available

Answer 17.9.3 The correct answer is "A." In general, erythema nodosum heals spontaneously in 3 to 6 weeks without scarring. There are treatment options available if the patient is symptomatic. If erythema nodosum is caused by an infection, that infection should be treated appropriately. If it was caused by a medication, such as an oral contraceptive pill, it should be discontinued. Nonsteroidal anti-inflammatory agents can be used to help with the pain. For patients with severe painful disease, systemic steroids can be considered.

Objectives: Did you learn to…

• Recognize erythema nodosum?

• Describe some of the causes and natural history of erythema nodosum?

Which of the following cause erythema multiforme?

A) Viral upper respiratory infection

B) Cimetidine

C) Herpes simplex outbreak

D) Nifedipine

E) All of the above

The correct answer is "E." All of the above are causes of erythema multiforme as are many, many other medications, etc. The most common precipitator of erythema multiforme is herpes simplex. Look for this association in your patients.

A patient presents to your office with a 1-week history of a pruritic rash that comes and goes. No lesion is present for more than 24 hours. It involves his entire body except for his face. He cannot remember any new products with which he has been in contact (soaps, detergents, etc.). He is quite concerned. You correctly diagnose urticaria.

Question 17.10.1 Your next step is:

A) Skin testing for various commercial products

B) Viral titers for CMV, EBV, etc.

C) RAST test for common allergens

D) Recommend no further evaluation.

E) Prescribe an epinephrine injection for emergency use at home

Answer 17.10.1 The correct answer is "D." No workup is needed at this time. Urticaria should be classified as "acute" (<6 weeks) or "chronic" (>6 weeks). Acute urticaria requires no further workup and should be treated symptomatically with antihistamines. In patients with chronic urticaria, a more detailed history should be taken looking for other symptoms or signs of infection, with laboratory testing as appropriate. In fact, beyond a good history, an extensive workup is pretty much futile. It is almost impossible to identify a cause of urticaria by laboratory testing. "E," an epinephrine injector, is not indicated for the treatment of urticaria but would be appropriate if this patient has experienced an anaphylactic reaction.

Question 17.10.2 Urticaria is categorized as which of the following?

A) Type I hypersensitivity reaction

B) Type II hypersensitivity reaction

C) Type III hypersensitivity reaction

D) Type IV hypersensitivity reaction

E) None of the above

Answer 17.10.2 The correct answer is "A." Urticaria is a clinical feature of a type I reaction. Other clinical presentations of type I reactions include anaphylaxis and angioedema. See Chapter 4 for a detailed answer on hypersensitivity reactions.

Question 17.10.3 You decide to provide symptomatic care for this patient. Appropriate medications include which of the following?

A) Ranitidine

B) Doxepin

C) Diphenhydramine

D) Cetirizine

E) All of the above

Answer 17.10.3 The correct answer is "E." All of the above can be useful in the symptomatic treatment of urticaria. Patients should be started on sedating and nonsedating anti-histamines to control their symptoms. Doses greater than the recommended daily dose are frequently required. H₂-blockers are effective in the 10% to 15% of patients who do not respond to H₁-blockers. Of note, H₂-blockers also are used in anaphylaxis treatment but the evidence is weak. Finally, doxepin is a particularly effective H₁- and H₂-blocker that can be used as a sedating antihistamine.

The patient returns to see you 6 weeks later and is still having symptoms. You are wondering a bit more about potential causes of this unfortunate individual's urticaria.

Question 17.10.4 Which of the following are causes of urticaria?

A) Sweating

B) Cold (OK, get over it. Move to Hawaii and quit whining!)

C) Water (So that is why you never shower and only drink beer?)

D) Pressure (OK, get over it. Use an antigravity unit and quit whining!)

E) All of the above

Answer 17.10.4 The correct answer is "E." All of the above can cause urticaria. In fact, these are not uncommon causes and can be identified by history. Patients may develop urticaria with exercise and sweating (cholinergic urticaria), cold (during the winter), and pressure (e.g., walking). Of particular note is water urticaria that occurs with water contact, including bathing and showering. See Table 17-2 for a more complete listing.

You decide that this patient probably has cold urticaria (the fact that it is summer does not dissuade you as it may be related to all of that air conditioning!).

Question 17.10.5 The next drug you might want to try on this patient is:

A) Cyproheptadine (Periactin)

B) Prednisone

C) Montelukast

D) Nifedipine

E) Aspirin

Answer 17.10.5 The correct answer is "A." The physical urticarias (cold and pressure especially) may respond better to cyproheptadine than other modalities. If this patient had a "typical" urticaria, you might want to try prednisone, one of the leukotriene inhibitors or nifedipine (which interferes with mast cell degranulation). Remember that leukotriene inhibitors, steroids, etc. are second line and should be used only when first-line drugs have failed or are not tolerated (cyproheptadine for physical urticaria; doxepin, anti-histamines, etc., for "typical" urticaria). There are no good studies on the effectiveness of leukotriene inhibitors (anecdotal evidence only), but they might be worth trying when all else fails.

Objectives: Did you learn to…

• Recognize urticaria?

• Identify potential causes of urticaria?

• Develop a treatment strategy for patients with urticaria?

Actinic keratoses (AKs) are precursors to what?

A) Nothing

B) Melanoma

C) Basal cell carcinoma

D) Squamous cell carcinoma

E) Granuloma annulare

The correct answer is "D." AKs are precursors to squamous cell carcinomas. As such, they should be treated. Options include cryotherapy, laser therapy, or 5-fluorouracil topically.

What is the appropriate treatment for an asymptomatic seborrheic keratosis?

A) No treatment necessary

B) Cryotherapy

C) Surgical excision

D) Topical steroids

E) Topical antibiotic ointment

The correct answer is "A." Seborrheic keratoses are benign lesions that do not develop into malignancies. They are the greasy-looking, stuck-on growths that occur with age. They can be treated, if symptomatic, with cryotherapy. They look ugly, patients hate them, but they are harmless.

A 50-year-old female with type 2 diabetes controlled with insulin complains of a rash that has developed on her legs over the past year. It started as a small patch on her left leg and then "spread" to her right leg. It is neither painful nor pruritic. You are impressed by the rash she shows you in Figure 17-17.

FIGURE 17-17. (Courtesy of Drs. Karolyn Wanat and Megan Noe.)

Question 17.11.1 The most appropriate next step in the management of these lesions is which of the following?

A) A topical mid-potency steroid under occlusion or intralesional steroids

B) Discontinue insulin

C) Increase her insulin dose

D) Liberal use of emollients (e.g., petrolatum)

E) Leg elevation and application of compressive stockings

Answer 17.11.1 The correct answer is "A." This patient has developed necrobiosis lipoidica, a benign condition of the skin affecting a small percent of diabetics, usually those on insulin. Look for brownish red patches or plaques with yellowish areas through the center. The center is often shiny with telangiectasias. The legs are most often involved and the lesions may be painful. The name describes the pathology: necrobiosis refers to the inflammation around destroyed collagen, and lipoidica refers to the yellowish color associated with lipid deposits. It does not seem to be caused by insulin or affected by glucose control, so "B" and "C" are not appropriate choices. These lesions can be confused for eczema, and in fact may respond to topical steroids ("A"); however, emollients are not useful. Finally, necrobiosis lipoidica might be confused with the skin changes associated with venous stasis and chronic edema, which would be treated as in "E." Patients should know that necrobiosis lipoidica is often chronic and difficult to treat but benign. The diagnosis is clinical but can be confirmed by biopsy, and treatment is not always necessary.

Your patient also complains of thick, dark, velvety patches under her arms (Fig. 17-18). She's unsure of the duration, but states, "They've been with me a while. I just wondered if my medication might cause these." She gives you an accusing look, and you have to admit that she takes more than a few medicines related to her diabetes.

FIGURE 17-18. Wolff K, Johnson RA, Suurmond D. Fitzpatrick's Color Atlas & Synopsis of Clinical Dermatology. 5th ed. New York: McGraw-Hill; 2005, Fig. 5–1. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.

Question 17.11.2 Which medication provides a clue to the diagnosis?

A) Aspirin

B) Lisinopril

C) Insulin

D) Simvastatin

Answer 17.11.2 The correct answer is "C." The lesions are typical of acanthosis nigricans, a hyperkeratotic, hyperpigmented condition affecting skin folds (neck, inguinal area, axilla, etc.). The common causes of acanthosis nigricans are obesity, insulin resistance, and diabetes. From med school, we all remember acanthosis nigricans as a cutaneous manifestation of internal malignancy. But such a presentation is rare. Cancer is more likely in patients with extensive and quickly progressing lesions, and as you might expect, it's not a good sign.

Your patient returns a year later and the lesions on her legs have essentially disappeared. Now she has a new concern. She reports a sore on the bottom of her great toe. She's uncertain how it occurred and thinks it has only been present for a few days. You find a 1-cm circular ulcer at the plantar aspect of her great toe. Pulses are diminished.

Question 17.11.3 Which of the following should be the next step in treatment?

A) Culture the wound

B) Perform an MRI of the foot

C) Perform monofilament testing to check sensation in the foot

D) Debride the wound

E) Obtain ankle–brachial indices

Answer 17.11.3 The correct answer is "E." The described wound is most likely a diabetic foot ulcer, but the location and the patient's history of diabetes do elicit concern for an ulcer related to vascular disease. Additionally, good vascular supply to the foot is necessary for wound healing. Therefore, you need to know the status of blood flow to the foot. This may be accomplished by physical examination. For patients at high risk for peripheral vascular disease or without strong pulses, ankle–brachial indices would be the next step. Culture of an open foot ulcer is pretty much worthless as it will likely return as polymicrobial. X-ray may be warranted as well as probing the lesion to see if it reaches the bone in order to evaluate for osteomyelitis, but MRI is jumping the gun. Knowledge of a patient's baseline sensation is important and good general foot care (shoes that fit, meticulous skin and nail acre) can help in the prevention of future ulcers. Wound debridement will help to remove necrotic tissue and improve the speed of wound healing. The biofilm must be removed down to healthy tissue in order to maximize healing.

Ankle–brachial indices in both legs are normal. The rest of her skin is in good condition. Through her diligent care and control of her diabetes, the ulcer heals. She returns 3 months later with a new skin concern. On her anterior shin, she has developed a clear fluid-filled blister about 1 cm in diameter and irregular in shape. There is no erythema, no pruritus, and no pain. She denies trauma and new environmental contacts.

Question 17.11.4 Which of the following is the most likely diagnosis?

A) Dyshidrotic eczema

B) Contact dermatitis

C) Staphylococcal scalded skin syndrome (SSSS)

D) Bullosis diabeticorum