Two cases of prurigo pigmentosa in atopic patients.

A 17-year-old man presented with pruritic confluent reticulated erythematous papules and hyperpigmented patches on his shoulders, abdomen and back that he had suffered with for 2 years (Fig. 1a). The condition had not responded to the previous treatments of oral antihistamines and topical steroids. He was reported to have had allergic rhinitis and allergic conjunctivitis, and these conditions spontaneously resolved during childhood and required no ongoing therapy. His mother and older sister also had allergic rhinitis. The physical exam showed erythematous papules and hyperpigmented brownish patches in a reticulated pattern that were symmetrically distributed on his trunk. He also had scaly brownish ichthyosiform patches on his flanks. The results of the laboratory tests including complete blood count, urinalysis, liver and renal function tests, the lipid profiles, and total immunoglobulin (Ig)E and eosinophil cationic protein (ECP) levels were within normal limits. He showed a strong positive response to the immediatetype allergy skin prick test with Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat fur and horse hair. There was no positive reaction on the patch tests using the Korean standard series. A biopsy specimen taken from the abdomen showed spongiosis and a few dyskeratotic cells in the epidermis and perivascular lymphocytic infiltrates and a few melanophages in the dermis (Fig. 2). Dapsone therapy at a dose of 100 mg daily was started. After 1 week of treatment, the erythematous papules were almost cleared up with some residual hyperpigmentation. A 23-year-old man presented with a 6-month history of pruritic erythematous eruptions over both sides of the neck. He had a typical course of erythema recurrently occurred on reticulated pigmentation over both sides of the neck and he denied exposure to any industrial chemical. He also had a chronic relapsing pruritic dermatitis that affected the flexural