Acquired Reactive Perforating Collagenosis on a Woman's Back

Highly pruritic, 2- to 4-mm, papular lesions with central ulceration erupted on the back of a 66-year-old woman (A and B). She had had 2 similar outbreaks in the past. The patient was taking conjugated estrogens, alprazolam, and alendronate. Dr Robert P. Blereau of Morgan City, La, performed a skin biopsy that confirmed the diagnosis of reactive perforating collagenosis. In this rare disorder, collagen is extruded from the dermis. The condition can be either inherited-which is more common-or acquired, as in this patient. The inherited variant begins in childhood and occurs most frequently on the dorsa of the hands and forearms. The outbreak of lesions appears to be precipitated by minor trauma. New lesions form as older ones involute, and scars may remain. The acquired disorder appears in adulthood and usually is associated with diabetes or chronic renal failure. This form of the disease also has been linked with Hodgkin disease, lichen amyloidosis, Wegener granulomatosis, rheumatoid arthritis, and Henoch-Schnlein purpura. No underlying cause was found in this patient. There is no specific treatment. Agents such as diphenhydramine hydrochloride and hydroxyzine pamoate may be used to relieve symptoms. Over time, this patient’s ulcerated lesions re-epithelized (C).