Herpes zoster is caused by reactivation of the varicella-zoster virus (the cause of chickenpox) from its latent phase.
A painful rash, usually crops of vesicles on an erythematous base, develops on one or more adjacent dermatomes.
Fewer than 4% of patients have another outbreak of zoster, but many, particularly the elderly, have persistent or recurrent pain for months or years (postherpetic neuralgia).
Antivirals (acyclovir, famciclovir, valacyclovir) are beneficial, especially for immunocompromised patients.
Analgesics are often necessary.
Give adults ≥ 60 yr a single dose of zoster vaccine whether they have had herpes zoster or not.