Photopatch testing: a six-year experience

The results of photopatch testing performed at the Mayo Clinic from 1980 through 1985 were analyzed. During the 6 years, 70 patients underwent photopatch testing. Of the 70 patients, 27 (38.5%) had positive photopatch test reactions and 22 (31%) had ordinary contact reactions. Of the 27 patients with photocontact reactions, 14 had relevant reactions. The most frequent positive reactions were to chlorpromazine (13 patients), musk ambrette (nine patients), and promethazine (eight patients). Photopatch testing is an essential part of the evaluation of patients who are suspected of having photosensitive dermatitis. In some patients with recalcitrant eruptions, testing may help in excluding photosensitivity as a possible contributing factor.