RESUMO
Reactive perforating collagenosis(RPC) is a kind of perforating dermatosis characterized by transepidermal elimination of altered dermal collagen. RPC is classified into two forms; childhood or inherited form, and adulthood or acquired form. Acquired RPC is reported to occur in association with the severe complicated diabetes mellitus, chronic renal failure and other diseases. We describe a 43-year-old Korean woman with atypical acquired RPC associated with uncontrolled diabetes mellitus and severe pruritus. The histopathologic findings of the lesions showed neither transepidermal channel nor cup-shaped epidermal depression. Multiple degenerated collagen bundles arranged vertically and were eliminated through epidermis to the surface individually. Transmission electron microscopic findings showed the same as typical RPC. Skin lesions improved after the insulin subcutaneous injections, UVB phototherapy and antihistamine administration.