The relationship between pityriasis rubra pilaris and inflammatory arthritis: case report and response of the arthritis to anti-tumor necrosis factor immunotherapy.

Pityriasis rubra pilaris (PRP) refers to a group of erythematous, scaling dermatologic conditions that have been associated with seronegative arthritis. We report a case of polyarthritis in a young man with PRP in which magnetic resonance imaging suggested an entheseal-based pathology for the joint disease. The arthritis, but not the skin condition, demonstrated dramatic response to anti-tumor necrosis factor immunotherapy.