Reactive perforating collagenosis - Skin in Adult
The pathogenesis is unknown, but the familial disease is generally thought be inherited in an autosomal recessive manner (although an autosomal dominant pattern has also been observed in some families). Males and females are equally affected, and lesions generally start within the first few years of life in the inherited form.
The primary lesion is generally a skin-colored papule 1-3 mm in diameter that reaches a maximum size of about 6 mm within a month; 6-8 weeks later, it regresses spontaneously (often leaving temporary areas of hypopigmentation behind or slight scarring). There is a central dark brown or black keratotic plug seen in more advanced lesions that is firmly adherent and, if removed, results in bleeding. Koebner phenomenon may occur, resulting in new lesions that are often linearly arranged. Pruritus is often severe. There are often periods of disease remission and exacerbation.
Lesions have a predisposition for the arms, legs, and face and are generally seen in relation to any form of skin trauma (even mild forms), including arthropod bites, cold exposure, folliculitis, scratching, and abrasions.
For more information on familial reactive perforating collagenosis, see OMIM.
L87.1 – Reactive perforating collagenosis
64036004 – Reactive perforating collagenosis
- Elastosis perforans serpiginosa – Lesions often occur in young adults rather than young children; they are also often annular or serpiginous and do not exhibit Koebner's phenomenon. The lesions generally only affect one anatomic area.
- Perforating folliculitis – Papules are generally asymptomatic, whereas lesions of reactive perforating collagenosis are very pruritic. The keratotic plug is generally white and often contains a curled-up hair in the center, in contrast to the dark brown or blacker keratotic plugs of reactive perforating collagenosis.
- Kyrle's disease – Lesions usually occur in adults (although rarely in children); they are usually bilateral and favor the lower extremities. The individual papules are generally reddish and often coalesce into plaques.
- Arthropod bites
- Papular urticaria
- Molluscum contagiosum
- Excoriations from various causes
- Prurigo nodularis
- Perforating of exogenous foreign material
- Perforating of endogenous foreign material
- Multiple keratoacanthomas