This violet-colored inflammation (erythema) over the knuckles is caused by Dermatomyositis. Other skin conditions produce more redness, while the color of this lesion is violet. There may also be inflammation in the muscle tissue.
Review Date: 4/27/2006
Reviewed By: Michael Lehrer, M.D., Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.