Acquired Reactive Perforating Collagenosis: Case Series.

Acquired reactive perforating collagenosis (ARPC) is one of the four acquired perforating dermatoses. The condition is characterized by transepidermal elimination of altered collagen. These are rare and underdiagnosed clinical entities and a few studies are available in the Indian literature. The present study described 15 patients of ARPC with underlying comorbidities and clinical response to systemic antihistamines, doxycycline, and topical clobetasol propionate. Of total 15 patients, 10 were men and the other five were women. Except two patients, diabetes mellitus was seen in 13 patients. Three patients had mild proteinuria. Four patients were known hypertensive. Itchy, papular, nodular lesions with central keratotic plug were seen commonly on the limbs and trunk. In another five patients, lesions were seen other than limbs and trunk, on the abdomen, chest, and back. In one case, giant plaques of more than 2 cm were present on the abdomen and limbs. In another patient, psoriasis lesions were concomitantly seen with ARPC lesions. Koebner's phenomenon was observed in six patients. The histopathological features of skin lesions in all 15 patients were consistent with ARPC. In all the patients, the lesions regressed within 4-6 weeks with topical clobetasol propionate and antihistamines. In three patients, systemic doxycycline was found to hasten the regression of lesions. Recurrences were observed in six patients during the follow-up period of 3 months.