Reactive Perforating Collagenosis

A 63-year-old woman who was on long-term hemodialysis because of diabetic end-stage renal disease had a 7-month history of waxing and waning papules and plaques on the front of both legs. The asymptomatic multiple, discrete, slightly erythematous, round to oval lesions ranged from 5 mm to 3 × 4 cm. Several had heaped-up borders and contained central crust and keratotic debris; others were superficial ulcers with central eschars. The lesions improved only slightly following twice-daily application of a superpotent topical corticosteroid preparation.

The differential diagnosis at this point included the primary perforating dermatoses, lichen planus, and perforating granuloma annulare. Examination of a biopsy specimen revealed the diagnosis of reactive perforating collagenosis (RPC), one of the primary dermatologic diseases that produce perforation of the epidermis and subsequent transepidermal elimination of altered material. In RPC, trauma results in a focus of subepidermal necrobiotic collagen. The overlying epidermis becomes disrupted, causing elimination of necrotic collagen bundles into a cup-shaped epidermal depression. In the other perforating diseases, various combinations of dermal debris, keratotic material, and degenerated elastic fibers are eliminated.

RPC is a rare disorder that may begin in infancy or childhood as an autosomal recessive condition, or it may develop in adulthood in association with diabetes mellitus or chronic renal failure. The lesions often involute spontaneously. If they do not, 0.1% tretinoin cream has been reported effective. The condition of the patient seen here, write Drs Eric J. Lewis and Charles E. Crutchfield III of Minneapolis, improved only slightly despite use of topical tretinoin, corticosteroid agents (both topical superpotent preparations and intralesional injection), and local wound care.