Herpes zoster (shingles)
Herpes zoster is reactivation of latent varicella-zoster virus from a sensory ganglion, producing a painful, dermatomal vesicular rash that does not cross the midline, most common in adults older than 60 years and in immunosuppressed hosts; diagnosis is clinical, confirmed by VZV PCR when needed, and antiviral therapy started within 72 hours of rash onset shortens the illness and reduces postherpetic neuralgia.
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What this article covers
- Overview
Herpes zoster (shingles) is reactivation of latent varicella-zoster virus (VZV, human herpesvirus 3) from a sensory ganglion, occurring after the virus established latency there during primary varicella (chickenpox) infection.
- Epidemiology
Incidence rises markedly after age 60 and continues to increase with advancing age, reflecting age-related decline in VZV-specific cell-mediated immunity (immunosenescence).
- Risk factors
Age older than 60 years, the dominant risk factor through immunosenescence.
- Pathophysiology
Primary varicella infection seeds sensory ganglia with latent VZV during the viremic phase of chickenpox, establishing lifelong dormancy in dorsal root or cranial nerve ganglia.
- Clinical features
Prodromal dermatomal pain, burning, or paresthesia, often preceding the rash by 1 to 5 days, is frequently the earliest symptom and can be mistaken for a cardiac, pleural, or abdominal process depending on the dermatome involved.
- Differential diagnosis
Herpes simplex virus infection: recurrent grouped vesicles at a non-dermatomal, often genital or oral, fixed site rather than a single dermatome, and lacks the prodromal neuralgic pain typical of zoster; see herpes simplex virus.
- Diagnosis
Herpes zoster is a clinical diagnosis based on the characteristic prodromal dermatomal pain followed by a unilateral, non-midline-crossing vesicular rash confined to that dermatome; confirmation is…
- Management
First, start oral antiviral therapy as soon as possible and within 72 hours of rash onset in every immunocompetent patient, because this window shortens the illness and reduces neuropathic pain…
- Complications
Postherpetic neuralgia, neuropathic pain lasting more than 1 month after rash resolution, is the most significant and most common complication and the main driver of long-term disability.
- Prognosis
Most immunocompetent patients recover from the acute rash without sequelae within 2 to 4 weeks, but a substantial minority, particularly older patients, go on to develop postherpetic neuralgia.
- Prevention
Recombinant zoster vaccine (2-dose intramuscular series, second dose 2 to 6 months after the first) is the most important preventive strategy and is recommended for immunocompetent adults 50 years…
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