RESUMO
BACKGROUND: Photopatch tests are used to diagnose photoallergic contact dermatitis and identify the causal agents. The frequencies of positive results and associated allergens vary by country; therefore, it is necessary to know the information specific to each country. OBJECTIVE: To establish the frequency of positive photopatch test results, and their relevance, in patients with suspected photoallergic contact dermatitis in a national dermatology centre located in Bogota, Colombia. MATERIALS AND METHODS: One hundred patients investigated for possible photoallergic contact dermatitis were enrolled in the study. They were photopatch tested with a selected group of allergens, and occluded for 48 hours; the duplicate right-hand panel was irradiated with 5 J/cm(2) ultraviolet (UV)A. The readings were performed on day (D)2, D4, and D6, in accordance with the guidelines of the ICDRG, and the relevance was evaluated with the COADEX system. RESULTS: There were a total of 20 photopatch reactions in 15 patients, 95% of which were caused by UV filters, most frequently benzophenone-3 (55%). Eight of the positive reactions (53.3%) appeared on D6. CONCLUSIONS: UV filters continue to be the most common causes of photoallergic contact dermatitis in our patients. Readings up to D6 (96 h after irradiation) are important to identify delayed positive reactions.
