An Unusual Case of Contact Dermatitis.

We report a case of acute psoriasiform contact dermatitis of the forehead and scalp related to the use of a low-laser light cap. The patient had a positive patch test to dimethylol dihydroxyethyleneurea (DMDE), methylisothiazolinone, kathon CG, and cobalt. We believe that DMDE in the fabric of the cap was responsible for the allergic contact dermatitis in this case as the lesions resolved with cessation of cap use.