Vesiculous prurigo pigmentosa in a 13-year-old girl: good response to isotretinoin.

Prurigo pigmentosa is a rare inflammatory disease of unknown origin, first reported from Japan, with only 33 cases described in non-Japanese patients. We describe a 13-year-old girl with a pruriginous symmetrical eruption of papules and vesicles affecting her back, neck and chest of 1 month duration. She remembered a similar, but lighter eruption, 2 months before. As the initial diagnosis was of a vesiculobullous form of Darier disease, treatment with isotretinoin 40 mg/day was started with good response. Histological study showed a superficial perivascular and interstitial dermatitis composed predominantly of lymphocytes. The epidermis was spongiotic, with exocytosis of lymphocytes and some neutrophils and necrotic keratinocytes. All these findings were consistent with prurigo pigmentosa. The lesions resolved leaving a light brown reticulate hyperpigmentation. Prurigo pigmentosa has never been reported in prepubescent patients, the vesiculobullous forms are unusual, and the only treatments used previously are sulphonamides, tetracyclines and macrolides. We report a 13-year-old Caucasian girl with vesiculobullous prurigo pigmentosa successfully treated with isotretinoin.