Treatment-resistant psoriasis due to a mastectomy sleeve: an extensive Koebner response.

The Koebner or isomorphic response refers to the appearance of a dermatosis at sites of trauma. This process was first described by Heinrich Koebner in a man with psoriatic plaques in areas of trauma. Many types of trauma are capable of producing koebnerization. We report a case of extensive koebnerization in response to the wearing of a mastectomy sleeve, worn to reduce lymphedema. Both the chronic pressure produced by the device and the trauma of applying the sleeve produced the necessary dermal and epidermal trauma to elicit the Koebner response.