Atypical Herpes Zoster

Several lesions had appeared 1 week earlier on the left distal thigh of a 47-year-old woman. The affected area featured erythema with irregular faded borders and central redness with very fine papules over the L3 dermatome. The indurated and tender central areas suggested inflammation or necrosis. There were no vesicles and there was no drainage. Dr Robert P. Blereau of Morgan City, La, performed an incisional biopsy of a lesion. Histopathologic examination of the specimen revealed reticular degeneration of the epidermis with multinucleated giant cells, nuclei with a ground-glass appearance, and intranuclear inclusions. Microscopically, lesions of herpes simplex, herpes zoster, and varicella are nearly identical. However, the degree of leukocytoclasia and hemorrhage seen in this specimen strongly suggested herpes zoster and, to a lesser degree, varicella. The lack of fluid-filled vesicles precluded the possibility of obtaining specimens for culture. Because the lesions had begun to resolve spontaneously by the time atypical herpes zoster was diagnosed, no specific treatment was offered to the patient. The diagnosis was further confirmed by the onset of postherpetic neuralgia of the thigh 5 weeks after the lesions first appeared. Low-dose oral amitriptyline and a series of epidural corticosteroid and local anesthetic injections alleviated the pain.