Varicella & Herpes Zoster

Essentials of Diagnosis

• Varicella rash: pruritic, centrifugal, papular, changing to vesicular ("dewdrops on a rose petal"), pustular, and finally crusting

• Zoster rash: tingling, pain, eruption of vesicles in a dermatomal distribution, evolving to pustules and then crusting

General Considerations

• Chickenpox is spread by inhalation of infective droplets or by contact with skin lesions

Demographics

• Disease manifestations include

  • Chickenpox (varicella), which occurs typically in children

  • Shingles (zoster), which occurs more commonly in elderly or immunocompromised persons

Symptoms and Signs

Varicella (chickenpox)

• Fever and malaise mild in children, marked in adults

• Vesicular eruptions often first involve oropharynx

• Rash involves face, scalp, and trunk and then moves out to the extremities

• Lesions erupt over 1–5 days so all stages of eruption present simultaneously

• Vesicles and pustules are superficial, elliptical, with slightly serrated borders

• Multinucleated giant cells on Tzanck smear of materials from vesicle bases

Herpes zoster (shingles)

• Pain is often severe and precedes the lesions

• Lesions follow any nerve route distribution (thoracic and lumbar most common)

• Vesicular skin lesions resemble varicella

• Lesions on tip of nose, inner corner of eye, and root and side of nose (Hutchinson sign) indicate potential ophthalmic involvement

• Facial palsy, vertigo, tinnitus, deafness, or external ear lesions suggest geniculate ganglion involvement

• Associations between recent attacks of zoster and the development of multiple sclerosis and Guillain Barré syndrome are recognized

Differential Diagnosis

Varicella (chickenpox)

• Herpes simplex (cold or fever sore; genital herpes)

• Herpes zoster (shingles)

• Contact dermatitis

• Scabies

• Atopic dermatitis (eczema) (acute)

• Miliaria (heat rash)

• Photodermatitis

• Smallpox

• Rickettsialpox

• Hand, foot, and mouth disease

Herpes zoster (shingles)

• Contact dermatitis (eg, poison oak or ivy)

• Herpes simplex

• Varicella (chickenpox)

• Erysipelas

• Prodromal pain mimics angina, peptic ulcer, appendicitis, biliary or renal colic

Laboratory Tests

• Leukopenia often present in varicella

• Zoster symptoms and signs often highly characteristic, not requiring further diagnostic testing

• When diagnosis remains in doubt, direct fluorescent antibody (DFA) testing, viral culture, and polymerase chain reaction (PCR) testing can be helpful

Diagnostic Findings

• Most patients with a history of exposure and clinical symptoms and signs of varicella do not need further diagnostic testing

• VariZIG reduces the severity of varicella in high-risk children or adults (eg, those with impaired immunity, pregnant women, and infants exposed peripartum) if given within 4 days of exposure

Medications

• Uncomplicated infection in otherwise healthy children and adolescents does not require antiviral therapy

• Varicella

  • Pruritus can be relieved with antihistamines, calamine lotion, and colloidal oatmeal baths

  • Fever can be treated with acetaminophen (not aspirin)

  • Acyclovir, 20 mg/kg (up to 800 mg per dose) orally four times daily for 5–7 days

    • Should be given within the first 24 hours after the onset of rash

    • Should be considered for patients older than 12 years, secondary household contacts, patients with chronic cutaneous and cardiopulmonary diseases, and children receiving long-term therapy with salicylates (to decrease the risk of Reye syndrome)

    • Hastens defervescence and healing of lesions but does not impact complication rates

  • High-dose acyclovir (30 mg/kg/day in three divided doses intravenously for at least 7 days; 10 days for encephalitis) should be started once the diagnosis is suspected

    • In immunocompromised patients

    • In pregnant women during the third trimester

    • In patients with extracutaneous disease (encephalitis, pneumonitis)

    • Acyclovir, 800 mg orally four times daily for 5–10 days, is alternative based on disease state treated

  • Famciclovir is not approved for persons under 18 years of age

  • Valacyclovir can be given between ages 2 and 18 at a dose of 20 mg/kg (maximum dose, 1 g) orally three times daily for 5 days

  • Corticosteroids may be useful in the presence of pneumonia

• For uncomplicated herpes zoster

  • Valacyclovir or famciclovir

    • Preferable to acyclovir due to dosing convenience and higher drug levels in the body

    • Therapy should start within the first 72 hours of the onset of the lesions and be continued for 7 days or until the lesions crust over

  • Corticosteroids (a tapering course starting at 60 mg/day, for 2–3 weeks)

    • Safe in immunocompetent patients

    • May be useful in hastening the resolution of acute lesions

    • Do not prevent the development of postherpetic neuralgia

  • Antiviral therapy reduces the duration of a herpetic lesion and associated episode of acute pain but does not decrease the risk of post-herpetic neuralgia

  • Intravenous acyclovir is used for extradermatomal complications of zoster

  • Adjunctive therapy may be considered in retinal disease (foscarnet) and acute herpes zoster (sorivudine, a topical antiviral)

  • Foscarnet may be used for acyclovir-resistant varicella zoster virus infections seen in immunosuppressed patients

Therapeutic Procedures

• Isolate patients with active vesicles or pneumonia from susceptible (seronegative) patients

Complications

Varicella (chickenpox)

• Secondary bacterial skin superinfections, particularly with group A streptococcus and Staphylococcus aureus

• Cellulitis, erysipelas and scarlet fever

• Bullous impetigo and necrotizing fasciitis seen less often

• Epiglottitis, necrotizing pneumonia, osteomyelitis, septic arthritis, epidural abscess, meningitis, endocarditis, pancreatitis, giant cell arteritis, inflammatory bowel disease, and purpura fulminans

• Toxic shock syndrome can also occur

• Interstitial pneumonia more common in adults than children

• Ischemic strokes, though uncommon, may be due to an associated vasculitis

• Hepatitis occurs in 0.1%

• Encephalitis

  • Infrequent (1:1000)

  • Occurs mostly in adults

  • Characterized by delirium, seizures, and focal neurologic signs

  • Mortality and long-term neurologic sequelae rates are 10%

• Reye syndrome may occur in conjunction with aspirin use, usually in children

• Congenital malformations occur with first-trimester infections

Herpes zoster (shingles)

• Postherpetic neuralgia

  • Occurs in 60–70% of elderly patients

  • Early treatment with acyclovir (or related drugs) and corticosteroids (tapered over 21 days) may have some benefit in preventing postherpetic neuralgia

• Other complications include

  • Bacterial skin superinfections

  • Herpes zoster ophthalmicus

  • Unilateral ophthalmoplegia (rarely)

  • Keratitis

  • Involvement of the geniculate ganglion of cranial nerve VII as well as cranial nerves V, VIII, IX and X nerves

  • Aseptic meningitis

  • Peripheral motor neuropathy

  • Transverse myelitis

  • Encephalitis

  • Acute cerebellitis

  • Stroke

  • Vasculopathy

  • Acute retinal necrosis

  • Progressive outer retinal necrosis (largely among the HIV infected)

  • Temporal arteritis

  • Sacral meningoradiculitis (Elsberg syndrome)

• Bell palsy in patients who are HSV seronegative

Prognosis

• Total duration of varicella from onset of symptoms to disappearance of crusts usually < 2 weeks

• Zoster symptoms and lesions usually resolve within 6 weeks

Prevention

• Varicella zoster vaccine reduces the incidence of zoster as well as the development of postherpetic neuralgia (Tables 30–7 and 30–8)

• Adjuvanted recombinant subunit vaccine (Shingrix)

  • Preferred over Zostavax

  • Recommended for adults 50 years and older

  • Particularly effective in reducing incidence of herpes zoster infection and postherpetic neuralgia in adults 70 years of age or older

• Live attenuated varicella zoster virus vaccine (Zostavax)

  • Recommended for patients 60 years of age or older

  • Reduces incidence of herpes zoster by 33–55% in first 3 years after vaccination

  • Reduces incidence of postherpetic neuralgia by 55–67%

• Varicella and zoster vaccines are not recommended for pregnant women

When to Refer

• Refer patients with synchronous progression of the lesions, which raises the concern for smallpox, to local health department and infectious disease experts for confirmation

When to Admit

• Consider hospitalization for signs of visceral involvement, especially pulmonary involvement. Varicella pneumonia can be lethal, especially in adults and in immunocompromised patients