A 55-year-old woman presents with severe itching on her arms and legs. The itching disrupts her sleep, and she sometimes scratches her arms and legs until exhaustion (Figures 155-1 and 155-2).1 She had used moisturizers, emollients, and topical corticosteroids, but they only alleviated the itching temporarily. The itching began 10 months earlier after finalizing the divorce from her husband of 20 years. The patient's right leg had been amputated above the knee after a car accident, and she now wore a prosthetic leg. The patient readily admitted to a great deal of psychological distress. She described feeling depressed since her divorce, and the loss of her leg further aggravated her situation. She has had difficulty securing a job and had high anxiety about being able to pay for rent and bills. The physician diagnosed an "excoriation disorder," and the patient understood that she was doing this to her own skin. The patient improved with nail cutting, topical clobetasol, and acknowledging the self-inflicted nature of her excoriations. One year later, the patient was working in the hospital laboratory with a tremendous improvement in her skin condition (Figure 155-3).
Excoriation disorder (neurodermatitis) seen on 3 of 4 extremities. The fourth extremity is a prosthetic leg. (Reproduced with permission from Usatine RP, Saldana-Arregui MA. Excoriations and ulcers on the arms and legs. J Fam Pract. 2004;53(9):713-716. Frontline Medical Communications. Inc.)
Excoriation disorder with close-up of arm. (Reproduced with permission from Usatine RP, Saldana-Arregui MA. Excoriations and ulcers on the arms and legs. J Fam Pract. 2004;53(9):713-716. Frontline Medical Communications. Inc.)
Same patient with excoriation disorder 1 year later after successful therapy. Hypopigmented scarring remains. (Reproduced with permission from Richard P. Usatine, MD.)
Psychocutaneous disorders (sometimes referred to as "self-inflicted dermatoses" or "psychogenic dermatoses") include excoriation disorder, lichen simplex chronicus, and prurigo nodularis. In these conditions, repeated scratching, skin-picking, rubbing, or other self-inflicted damage to the skin occurs for psychiatric reasons, without evidence of a primary medical or dermatologic disorder. Psychocutaneous disorders can present a challenge to the clinician, as multiple underlying medical etiologies must be ruled out to arrive at their diagnosis and the pathophysiology of these diseases is not well understood. In addition, these disorders may be difficult to treat successfully. There is no clear standard of care for treatment, although a vast array of treatments targeting different etiologies has been tried clinically, and many have some amount of research to support them. As with other psychosomatic conditions, nonpharmacologic interventions, including the physician–patient relationship itself, are important to treatment.
Excoriation (skin-picking) disorder was established as a separate psychiatric diagnosis in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)2 in 2013. It is grouped under obsessive–compulsive and related disorders. In addition to the presence of recurrent, time-consuming skin picking, essential features of the diagnosis include repeated attempts to stop or decrease the skin picking, impairment in functioning or clinically significant distress, and that other conditions do not account for the skin picking (including delusional parasitosis, tactile hallucinations, nonsuicidal self-injury, or the presence of scabies).
Excoriation disorder—Skin-picking disorder; neurotic excoriations; neurodermatitis.
Lichen simplex chronicus—Neurodermatitis circumscripta; neurodermatitis.
Prurigo nodularis—Picker's nodules; lichen simplex chronicus, prurigo nodularis type; atypical nodular form of neurodermatitis circumscripta; skin-picking disorder.
Excoriation disorder primarily affects females, with onset usually occurring during adolescence2 (Figures 155-1, 155-2, 155-3, 155-4, 155-5).
Excoriation disorder is present in 2% of patients seen in dermatologic clinics,3 and lifetime prevalence in the general population may be as high as 5.4%.4
Lichen simplex chronicus (LSC) is observed more commonly in females than in males5 (Figures 155-6, 155-7, 155-8, 155-9). Lichen nuchae is a form of lichen simplex that occurs on the midposterior neck (Figures 155-8 and 155-9).
LSC occurs mostly in mid-to-late adulthood, with highest prevalence in persons ages 30 to 50 years.5,6
For prurigo nodularis (PN) there is no documented difference in frequency between males and females. PN most often occurs in middle-aged and older persons7 (Figures 155-10, 155-11, 155-12, 155-13, 155-14, 155-15).
Excoriation disorder on the leg with significant postinflammatory hyperpigmentation. (Reproduced with permission from Richard P. Usatine, MD.)
Excoriation disorder (skin-picking) on the upper arm with hypopigmented scarring. (Reproduced with permission from Richard P. Usatine, MD.)
Lichen simplex chronicus on the hand of a middle-aged woman with thick lichenification, erythema, and hyperpigmentation. She was continually scratching at her hand. (Reproduced with permission from Richard P. Usatine, MD.)
Lichen simplex chronicus on the ankle. (Reproduced with permission from Richard P. Usatine, MD.)
Lichen simplex chronicus on the neck of a Hispanic woman who also has acanthosis nigricans. (Reproduced with permission from Richard P. Usatine, MD.)
Lichen simplex chronicus on the neck of a Hispanic woman with thick plaque formation that resembles prurigo nodularis. (Reproduced with permission from Richard P. Usatine, MD.)
Prurigo nodularis on the arms and legs of a 42-year-old Hispanic woman. (Reproduced with permission from Richard P. Usatine, MD.)
Prurigo nodularis on the arms and legs after 9 months of unsuccessful treatment in the patient in Figure 155-10. (Reproduced with permission from Richard P. Usatine, MD.)
Severe prurigo nodularis on the arm. The nodules are somewhat linear from years of scratching. (Reproduced with permission from Richard P. Usatine, MD.)
Prurigo nodularis on the upper back of a man. (Reproduced with permission from Richard P. Usatine, MD.)
A cluster of nodules on the back of the same patient with prurigo nodularis. (Reproduced with permission from Richard P. Usatine, MD.)
Severe prurigo nodularis on the legs with prominent hyperpigmentation of the nodules and some secondary infection. (Reproduced with permission from Richard P. Usatine, MD.)
ETIOLOGY AND PATHOPHYSIOLOGY
All 3 conditions are found on the skin in regions accessible to scratching.
Excoriation disorder is considered a psychiatric diagnosis on the obsessive–compulsive spectrum. It often begins with benign picking either of normal skin or of mild skin diseases, such as acne, before becoming pathologic.2-4
Negative affective states such as tension, anxiety, or boredom may directly trigger neurotic picking and excoriations.4
In all three disorders, pruritus may occur, provoking scratching that produces clinical lesions. This is particularly true in LSC and PN.
The underlying pathophysiology is unknown for all 3 conditions. Central nervous system (CNS)8 and peripheral nervous system9,10 dysfunction have been implicated in the pathogenesis of the pruritus underlying psychocutaneous disorders.
Some skin types are more prone to lichenification, such as skin that tends toward eczematous conditions (i.e., atopic dermatitis).6
The pathogenesis of PN is still unknown. PN shares some histologic features (epidermal proliferation) with psoriasis and ichthyosis, but is largely self-inflicted.7 There is some evidence to suggest that immune dysregulation is involved, as PN is more common in patients with HIV/AIDS (pruritic papular eruption) and other forms of immunosuppression than in the general population.7 Some histologic studies have shown changes in intraepidermal nerve fibers, suggesting the presence of a subclinical small-fiber neuropathy.11
Self-inflicted damage to the skin by repeated scratching, rubbing, or picking—which the patient readily admits to—is a typical finding for these psychocutaneous disorders. The patient will often complain of intense itching. Common psychiatric problems associated with these disorders include significant social stress, depression, anxiety, and obsessive–compulsive disorder. Patients are often observed scratching and rubbing their skin. This results in:
Common physical examination findings for all three disorders include:
Excoriation disorder—Skin lesions may vary from dug-out erosions, to ulcers covered with crusts and surrounded by erythema, to areas receding into hypopigmented depressed scars (see Figure 155-5).
Lichen simplex chronicus—One or more slightly erythematous, scaly, well-demarcated, lichenified, firm, rough plaques (see Figures 155-6, 155-7, 155-8, 155-9).
Prurigo nodularis—Raised nodules from 2 to 20 mm, colors vary from shades of red to brown (see Figures 155-10, 155-11, 155-12, 155-13, 155-14, 155-15). Excoriations are almost always present on initial presentation. With treatment the excoriations may subside and the nodules may remain.
Excoriation disorder occurs on areas easily reached by the patient, such as the arms, legs, and upper back (see Figures 155-1, 155-2, 155-3, 155-4, 155-5).
LSC occurs on:
In PN, nodules occur on the extensor surfaces of the arms, the legs, and sometimes the trunk (see Figures 155-10, 155-11, 155-12, 155-13, 155-14, 155-15).
A comprehensive medical profile may be useful to make sure that the pruritus is not related to renal or hepatic disease.
Punch biopsy may be helpful when the diagnosis is uncertain.
Acne keloidalis nuchae—Acneiform eruption at the hairline from ingrown hairs, worse with shaving and short haircuts (see Chapter 120, Pseudofolliculitis and Acne Keloidalis Nuchae).
Atopic dermatitis—An allergic skin disorder in patients with a personal or family history of atopic conditions. Patients with atopic dermatitis are more likely to get LSC (see Chapter 151, Atopic Dermatitis).
Contact dermatitis—A common inflammatory skin condition characterized by erythematous and pruritic skin lesions resulting from the contact of skin with a toxic substance or a contact allergen (see Chapter 152, Contact Dermatitis).
Delusions of parasitosis (Delusional parasitosis or delusional infestation)—Delusions that tiny bugs or parasites are living on or below the patient's skin, leading them to try to dig them out with their fingernails and other devices. This condition may look just like excoriation disorder; however, the patient believes there are parasites causing the pruritus, and it is very difficult to convince them otherwise.
Dermatitis artefacta (factitious dermatitis)—A condition in which individuals deliberately damage their skin in order to receive medical care.
Nonsuicidal self-injury—Self-inflicted harm (such as cutting) that is not intended to produce death. The person may cut their skin to self-punish or relieve extreme emotional distress. This psychological distress is more acute in nature than the anxiety and tension that may trigger habitual skin picking.
Nummular eczema—Eczematous lesions in the shape of coins, seen most often on the legs.
Scabies—Look for burrows between the fingers and other typical distribution sites of scabies on the hands, feet, wrists, waist, and axillae to differentiate scabies from a psychocutaneous disorder. Scraping lesions and finding evidence of the scabies mite is the best way to confirm a true scabies infestation. Often family members have itching and lesions as well when the real diagnosis is scabies (see Chapter 149, Scabies).
Get a good psychosocial history and offer the patient treatment for any problems uncovered. It may help for patients to understand the connection between their self-inflicted lesions and their stressors. Some patients will have anxiety disorders or depression, whereas others will be suffering with great psychosocial stressors like loss of work, homelessness, or grief. Offer pharmacotherapy (including selective serotonin reuptake inhibitors [SSRIs]) and counseling if indicated. Refer as needed for these therapies. Other specific treatments to consider are listed below for each disorder.
SSRIs as a class have been reported in one meta-analysis to be effective for excoriation disorder with a large effect size.12 However, another meta-analysis concluded there was insufficient evidence that SSRIs were superior to non-treatment control conditions.13 Given their efficacy in several psychiatric disorders that may be comorbid with excoriation disorder and the existence of positive randomized controlled trials for SSRIs in excoriation disorder, we recommend that SSRIs be considered early in treatment, either in combination with psychotherapy or if there is insufficient response with psychotherapy alone. SORⒷ
Topical or oral antibiotics should be prescribed if secondary infection is present. SORⒸ
If pruritus is present:
Topical corticosteroids—use mid-potency to high-potency steroids except in areas of thin skin. Steroid creams are usually used, but steroid ointments are preferred if deeper excoriations or ulcers are present.1 SORⒸ
Oral antihistamines such as hydroxyzine. SORⒸ
Oral low-dose doxepin, a tricyclic antidepressant with sedating properties (10–25 mg at night).3 SORⒸ
In general, topical glucocorticoid creams or ointments are the first-line treatment.5,6,16,17 SORⒷ High- or ultrahigh-potency topical steroids may be used for short (i.e., up to 6 weeks) courses and may need to be tapered. For longer term use, midpotency steroids may be used.
Topical glucocorticoid creams or ointments.22 SORⒸ
Oral antihistamines.23 SORⒸ
Intralesional steroids such as triamcinolone5,7,22-24—start with 5–10 mg/mL; some authors recommend increasing as needed, up to 40 mg/mL.22 SORⒸ
Topical capsaicin is recommended by some experts.22-25 SORⒸ Explain to the patient that this stings and burns the skin and mucus membranes before it works.
Referral to dermatology, psychotherapy, and/or psychopharmacology should be considered in any of these disorders that do not respond to treatment in the primary care setting. Hospitalization is rarely needed.
Help patients to understand that they are unintentionally hurting their own skin. Patients need to minimize touching, scratching, and rubbing affected areas. Suggest that patients gently apply their medication or a moisturizer instead of scratching the pruritic areas. Give patients hope and show them Figures 155-1, 155-2, 155-3 to demonstrate that even the most severe cases can heal if they stop manipulating their skin.
Follow-up is essential because these problems are chronic and difficult to treat. Patients need to know that you will not abandon them but will continue to work with them to get relief. This is especially important when the patient is suffering from anxiety, depression, or other psychological problems.
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