Reactive perforating collagenosis

To the Editor,

Reacting perforating collagenosis (RPC) is a genetically determined disorder with predisposition to an unusual skin reaction to superficial trauma.[1] As result of trauma, the collagen in the papillary layer of dermis becomes altered and causes irritation and then perforation of epidermis with transepidermal elimination of necrobiotic material. Usually it is a disease of childhood. In this communication, 5 patients with RPC in 2 unrelated families, 3 from one and 2 from the other, who came to hospital within 1 month duration are being reported.

Family A consisted of an 8 years old boy and his 7 years old sister. They have been developing hyperkeratotic wart like lesions since early infancy. The lesions always appeared following minor injury or even after insect bite. The sites involved are dorsa of hands, forearms, elbows and knees in both children while in brother even face was also involved. The lesions showed a central area of depression containing an adherent keratotic plug which could be easily extruded out in form of whitish material. Some lesions were also present along scratch marks indicating Koebner′s phenomenon. The lesions heal in 6-8 weaks with hypopigmented macule.

In family B, father and his 2 sons, 5 years and 8 years old, have been developing similar hyperkeratotic wart like lesions after injury. Lesions followed similar course as in patients of family A. Patients did not agree for biopsy.

The occurrence of disease in same family confirms genetic origin. Appearance of 5 cases within 1 month duration suggest that RPC in not as rare an entity as was earlier considered and thus must be considered in differential diagnosis of cases of papular eruption of childhood.[2]