Herpes Zoster/Shingles

The diagnosis is usually clinical and is based on the characteristic appearance and distribution of lesions. If the diagnosis is uncertain, perform viral cultures or antigen detection by direct fluorescent antibody from a freshly opened vesicle or biopsy from the border of a lesion.

	Treatment ideally should begin within 72 hours of an outbreak or while new lesions are appearing. Famciclovir (Famvir) 500 mg orally 3 times per day for 7-10 days or valacyclovir (Valtrex) 1 g orally every 8 hours for 7 days is the preferred regimen and may attenuate a herpes/VZV attack if started early.
	An alternative treatment is acyclovir 800 mg orally 5 times per day.
	Dosage reductions of these drugs are required for patients with renal impairment.
	If new blisters are still appearing at the end of treatment, repeat course of oral therapy or consider intravenous treatment. Adjunctive corticosteroids aimed at preventing postherpetic neuralgia are not recommended.
	Consult an ophthalmologist immediately if lesions appear in the eye area or on the tip of the nose, or if patient complains of visual disturbances, because VZV-related retinal necrosis can cause blindness. Because of the rapid progression associated with this diagnosis, hospitalization for intravenous acyclovir and possibly foscarnet is recommended.
	VZV from zoster lesions is contagious, and contact or airborne spread from vesicle fluid may cause chickenpox in nonimmune people. If a zoster patient's household includes a pregnant woman (HIV infected or uninfected) or an HIV-infected child, consult with a specialist immediately for advice on management of exposed household members. (See "Postcontact Chickenpox Prevention" below.)
	Give analgesics for pain; narcotics may be required.
	Antiviral therapy may reduce the risk of postherpetic neuralgia, but if it does occur, special pain control techniques will be required: Nortriptyline 10-20 mg should be taken every night at bedtime and increased until pain is controlled and adverse effects remain tolerable. Other tricyclics may be used. Lidocaine 5% patches provide good local relief with minimal systemic absorption. Up to 3 patches may be applied simultaneously to the affected area for up to 12 hours in a 24-hour period. Gabapentin is given at 100-300 mg orally 3 times per day; this may be increased until reaching 3,600-mg total daily dosage. Sustained-release opiates may be required.

(See chapter Pain Syndrome and Peripheral Neuropathy for more options and specific recommendations.)

Severe or unresponsive cases

Intravenous acyclovir may be indicated if: The patient is severely immunocompromised The ophthalmic branch of the trigeminal nerve is affected (as noted above) Dissemination has occurred Lesions are not responsive to oral therapy Pain is intractable The usual adult dosage is 10-12 mg/kg every 8 hours for 7-14 days; dosage reduction is required for patients with renal impairment. Refer to an infectious disease specialist. Acyclovir resistance may occur in patients previously treated with acyclovir or related drugs, and foscarnet may be required for effective treatment. Resistance should be suspected if lesions are not resolving after 10 days of therapy or if they develop a verrucous appearance. Such lesions should be cultured and drug sensitivities should be obtained.

All persons, including pregnant women, who have close contact with a patient who has chickenpox or shingles must be treated to prevent chickenpox. Those who have no history of chickenpox or shingles or no detectable antibody against VZV should be administered varicella zoster immune globulin as soon as possible, but at least within 96 hours after contact. Even immunocompetent adults with primary VZV (chickenpox) can develop viral dissemination to the visceral organs. HIV-infected patients may develop encephalitis, pneumonia, or polyradiculopathy during primary zoster (chickenpox) or reactivated zoster (shingles).