Herpes zoster

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Herpes zoster is "an acute infectious, usually self-limited, disease believed to represent activation of latent varicella-zoster virus in those who have been rendered partially immune after a previous attack of Chickenpox. It involves the sensory ganglia and their areas of innervation and is characterized by severe neuralgic pain along the distribution of the affected nerve and crops of clustered vesicles over the area."^[1]

Epidemiology[edit]

For adults over 60 years of age, the incidence is about 1% per year.^[2]

Prevention[edit]

The Centers for Disease Control recommends the zoster vaccination (Zostavax - which is different than the pediatric vaccine Variva) for adults aged at least 60 years:^[3] Contraindications include:^[4]

• allergic to neomycin, or any component of the vaccine
• immuncompromise due to radiation, corticosteroids, or conditions such as AIDS and cancers.
• pregnancy
• people who are in close contact with pregnant women who have not had chickenpox probably not have vaccine

A randomized controlled trial of a vaccine for adults aged at least 60 years reduced the incidence of zoster over three years by about one-half - from a rate of 3.3% down to 1.6%; approximately 60 people would have to take the vaccine to prevent one case of shingles (number needed to treat=59).^[5] A more recent cohort study in a community setting estimated similar effect.^[6]

In the United States, the vaccine is more expensive than many other vaccines, and its cost may be a factor with some third-party payors, or with the target older population of limited income. Some public health programs, however, are aggressive at providing it to that target group.

Treatment[edit]

Combining antiviral agents with a corticosteroid may reduce the incidence of postherpetic neuralgia.^[7][8]

Early tricyclic antidepressant^[9] or gabapentin^[10] may help.

Postherpetic neuralgia[edit]

While the acute phase is uncomfortable, the greatest concern is that some patients may develop postherpetic neuralgia. If postherpetic neuralgia develops, there are a number of therapies. Comparative studies suggest that tricyclic antidepressants such as desipramine^[11] and opioid analgesics such as oxycodone^[12] are more effective than anticonvulsants such as gabapentin and pregabalin. Other options include topical lidocaine^[13] and topical capsaicin.

These therapies are not mutually exclusive. A clinician may choose, for example, to use an anticonvulsant or antidepressant in combination with opioid analgesics.

References[edit]