Once an individual has been exposed to varicella-zoster virus, either from primary infection (chickenpox) or vaccination, the virus remains dormant in dorsal root ganglion cells. It may become reactivated at a later time, which results in herpes zoster. Typically, immunosuppression (hematologic malignancy and HIV infection) and age are factors that play a role in reactivation, although young people may develop shingles as well. Older age increases the incidence of herpes zoster.
More than 90% of patients will experience a prodrome of pain, burning, or tingling in the dermatome prior to the development of cutaneous lesions. Occasionally, there will be no symptoms prior. Papules and plaques begin to form, which quickly develop into vesicles and blisters. After a few days, lesions become crusted. Bullae or necrosis may occur in more severe cases. Typically, the condition resolves in 2-3 weeks, but can take 6 weeks or longer in elderly patients. In zoster sine herpete, patients have pain but no skin lesions.
In typical herpes zoster, lesions can be scattered outside the dermatome as well. When more than 20 lesions are scattered outside the area of primary or adjacent dermatomes, this is defined as disseminated herpes zoster. This occurs more commonly in debilitated or immune-compromised individuals. The outlying vesicles are often singular, not grouped, and resemble the “dew drop on a rose petal” look of varicella-zoster lesions. Dissemination necessitates systemic antiviral therapy, preferably intravenous followed by oral treatment once stable. Central nervous system and pulmonary involvement can occur.
Complications of zoster can occur. Postherpetic neuralgia and pain is more common in patients over the age of 50 and may become chronic. Ramsay Hunt syndrome may result in facial paralysis and hearing loss when there is involvement of the facial or auditory nerve. Occasionally, inflammatory lesions can occur within the affected area after the infection has resolved. Secondary bacterial infection, scarring, and motor paralysis can occur.
Dr. Bilu Martin is a board-certified dermatologist in private practice at Premier Dermatology, MD, in Aventura, Fla. More diagnostic cases are available at edermatologynews.com. To submit a case for possible publication, send an email to firstname.lastname@example.org. This case and photo were submitted by Dr. Bilu Martin.