Skin testing with simple equipment in photodermatoses

We have reviewed 275 patients who were tested in the light testing clinic in the 10 years from 1972 to 1981. 151 patients (55%) were referred with eczematous changes of the skin attributed to light, while 76 (28%) had a history of polymorphic light eruption. Light tests gave abnormal results in 54 (36%) of the dermatitis group, showing a photoallergy in 17 patients and UV sensitivity with or without sensitivity to visible light in 30 patients. 7 out of 10 cases with clinical reactions to phenothiazines also had abnormal test results. Patients with polymorphic light eruption reacted normally in our test system. Abnormal tests were obtained in solar urticaria, in a few cases of non-eczematous phototoxic reactions, folliculitis of the acne type and systemic lupus erythematosus. Additional patch tests with standard allergens revealed a high % of contact sensitivity in the 30 UV sensitive patients.