Varicella & Herpes Zoster

KEY FEATURES

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

• Varicella (chickenpox)

  • Spread by inhalation of infective droplets or by contact with skin lesions

  • Occurs typically in children

  • Incubation period is 10–20 days (average 2 weeks)

• Herpes zoster ("shingles") occurs more commonly in older or immunocompromised persons

• Populations at increased risk for varicella-zoster–related diseases include immunosuppressed persons and persons receiving biologic agents

Demographics

• Incidence and severity of herpes zoster

  • Affects up to 30% of persons during their lifetime

  • Increases with age due to an age-related decline in immunity against varicella-zoster virus (VZV)

  • More than half of all patients in whom herpes zoster develops are older than age 60 years

  • Incidence of herpes zoster reaches 10 cases per 1000 patient-years by age 80 (by which time 50% are infected with VZV)

  • The annual incidence in the United States is 1 million cases and increasing as the population ages

CLINICAL FINDINGS

Symptoms and Signs

Varicella (chickenpox)

• Fever and malaise mild in children, marked in adults

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

• Maculopapules change within a few hours to vesicles that become pustular and eventually form crusts

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

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

• The crusts slough in 7–14 days, with slightly serrated borders

• Pitted scars are frequent

• More severe in older patients

• In immunocompromised persons, there can be widespread dissemination in the absence of skin lesions

Herpes zoster ("shingles")

• Superficial sensory symptoms such as pain are often severe and precede the lesions by several days

• Lesions follow any nerve route distribution (thoracic and lumbar most common) and involve one (most common) or multiple dermatomes; disseminated disease is defined by involvement of three or more dermatomes

• Vesicular skin lesions typically develop into clusters of vesicles over 3–5 days and can be painful or pruritic

• In untreated immunocompetent individuals, lesions take 2–4 weeks to heal (dry and crust over) and can leave hyperpigmented macular scars

• 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 (Ramsay Hunt syndrome or herpes zoster oticus)

DIAGNOSIS

• Because both infections have characteristic clinical signs, diagnostic testing is usually not necessary

Laboratory Tests