11.18 Herpes Zoster (Shingles)

agk’s Library of Common Simple Emergencies

Presentation: Patients complain of pain, paresthesia, or an itch that covers a specific dermatome and then develops into a characteristic rash. Prior to the onset of the rash, zoster can be confused with pleuritic or cardiac pain, cholecystitis, or ureteral colic. Approximately 3-5 days from the onset of symptoms, an eruption of erythematous macules and papules will appear, first posteriorly then spreading anteriorly along the course of the involved nerve segment. In most instances grouped vesicles will appear within the next 24 hours. Herpes zoster most often occurs in the thoracic and cervical segments.

What to do:

• Prescribe acyclovir (Zovirax) 800mg q4h (five times a day, skip a dose at night) or famiclovir (Famvir) 500mg tid x7d.
• Prescribe analgesics appropriate for the level of pain the patient is experiencing. Anti-inflammatory medications may help, but narcotics are often required (e.g., Percocet q4h).
• Cool compresses with Burow’s solution will be comforting (e.g Domeboro powder, 2 pkts in 1 pint of water).
• Dressing the lesions with gauze and splinting them with an elastic wrap may also help bring relief.
• Secondary infection should be treated with povidone-iodine (Betadine) ointment or systemic antibiotics.
• Ocular lesions should be evaluated by an ophthalmologist and treated with topical ophthalmic corticosteroids. Although topical steroids are contraindicated in herpes simplex keratitis, because they allow deeper corneal injury, this does not appear to be a problem with herpes zoster ophthalmicus. If the rash extends to the tip of the nose, the eye will probably be involved, because it is served by the same ophthalmic branch of the trigeminal nerve.

What not to do:

• Do not prescribe systemic steroids to prevent post herpetic neuralgia, especially for patients at high risk, i.e., with latent tuberculosis, peptic ulcer, diabetes mellitus, hypertension, and congestive heart failure.

Discussion

Zoster results from reactivation of latent herpes varicella/zoster (chickenpox) virus residing in dorsal root or cranial nerve ganglion cells. Two-thirds of the patients are over 40 years old. This is a self-limiting, localized disease and usually heals within 3-4 weeks. Postherpetic neuralgia in patients over 60 years old, however, can be an extremely painful, recurrent misery. Before the availability of anti-viral agents, the best prophylaxis was systemic corticosteroids, but these have not been shown to improve outcome when added to a week of anti-viral treatment.

References:

• Wood MJ, Johnson RW, McKendrick MW, Taylor J, Mandal BK, Crooks J: A randomized trial of acyclovir for 7 days or 21 days with and without prednisolone for treatment of acute herpes zoster. N Eng J Med 1994;330:896-900.

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