Reactive perforating collagenosis and phototraumatism.

Two pairs of siblings are reported suffering from reactive perforating collagenosis. The clinical features were recurrent crusted papules with a central keratinaceous plug. The plug was sometimes encircled by a narrow yellowish ring and a wider red ring, giving the appearance of a cockade. Lesions recurred spontaneously or were provoked by superficial injury to sun-exposed skin (phototraumatism). There were no other changes in the general health of these patients.