A three-year photopatch study in Thailand.

Photopatch testing was performed on 274 patients who had history of photosensitivity at the Institute of Dermatology Thailand from 1987 through 1989. A total of 92 positive photocontact reactions and 71 positive contact reactions were seen. The most frequent positive photopatch test reactions were to sulfanilamide (18.2%) followed by Jadit (4.4%) chlorpromazine (3.6%) promethazine (3.6%) and fenticlor (3.2%). The most common photodermatoses was polymorphous light eruption (60.9%). Photocontact dermatitis was established in 28 patients (10.2%) while other skin diseases aggravated by sunlight were seen in 47 patients (17.2%).