Herpes zoster (shingles) usually begins with a 1- to 2-day prodrome of pain or burning in a dermatomal distribution. The discomfort of zoster is deep like a neuralgia or superficial on the skin. The pain can be severe. In the chest or abdominal locations, prodromal pain can mimic cardiac, musculoskeletal, or intraperitoneal diseases.

The eruption consists of red papules or clear vesicles on a red base. The lesions, 2 to 4 mm in diameter, are frequently umbilicated, can be individual or grouped and are in a dermatomal distribution (Fig. 29-1). They often progress to confluent vesicles, which then erode and crust over. Secondary bacterial infection is common. Older patients are more likely to develop extensive involvement and severe pain. In severe cases and in immunocompromised patients, more than a single dermatome can be affected.

Herpes zoster is caused by the reactivation of varicella-zoster infection (chickenpox), usually suffered years before.

Herpes simplex recurrences are dermatomal, but typically appear on the lip or genitals. Insect bites, folliculitis, and tinea capitis can look the same as herpes zoster on the scalp. Cellulitis and erysipelas have considerable edema and erythema, especially when they affect the face. Human immunodeficiency virus (HIV) infection should be considered in all patients with herpes zoster.