A Rare Case of Familial Reactive Perforating Collagenosis
A 4 year old boy presented with complaints of multiple, recurrent, dark coloured raised lesions on face, elbows and outer aspect of both legs of 2 years duration. The lesions would start as skin coloured papules which later developed dark central material. Some of the lesions would heal on its own in about a month leaving behind residual hyperpigmentation. Associated severe itching was present in all lesions. Patient's mother complained that she had noticed new lesions occurring at sites of trauma. There was history of similar complaints in his elder brother who was staying with his grandparents. There was no parental consanguinity.\nDermatological examination revealed multiple, discrete, symmetrical, hyperpigmented, hyperkeratotic papules distributed over face, both elbows and lateral aspect of both legs []. Most of the lesions showed a central keratotic plug. There was evidence of koebnerisation at multiple sites []. Systemic examination was essentially normal.\nRoutine lab investigations were normal. Skin biopsy from the lesion showed stratified squamous keratinised epidermis. Epidermis showed a hyperkeratotic crater filled with keratin, few polymorphonuclear leucocytes and occasional acellular basophilic fibrous strands. The shoulder of the crater shows marked acanthosis. The adjacent papillary dermis showed vertically oriented collagen bundles perforating the epidermis []. Moderate perivascular chronic mononuclear cell infiltrate was seen. The perforating collagen bundles were better delineated on Van Gieson stain []. Based on clinical and histopathological features, a diagnosis of reactive perforating collagenosis was made. The patient was started on topical tretinoin 0.05% cream and intralesional corticosteroids. The lesions showed some flattening with therapy but the patient continued to get new lesions at sites of minor trauma.