A 20-year analysis of previous and emerging allergens that elicit photoallergic contact dermatitis

Background: Retrospective chart reviews are periodically needed to update allergen series to detect changes in photoallergic contact dermatitis (PACD) over time. Objective: We sought to evaluate photopatch test results during a 13-year period and extend the observations to 20 years. Methods: A retrospective chart review was conducted in patients who were photopatch tested. Results: In all, 76 patients were evaluated A total of 69 positive photopatch and 45 positive patch test reactions were detected in 30 and 23 patients, respectively. The frequencies of the positive photopatch test reactions were Sunscreens 23.2%, antimicrobial agents 23.2%, medications 20.3%, fragrances 13%, plants and plant derivatives 11.6%, and pesticides 8.7%. Of the positive photopatch reactions to antimicrobial agents, 60% were caused by Fentichlor. Limitations: This study was a retrospective chart analysis, and the number of patients was small. Conclusions: Sunscreens and antimicrobial agents were the most frequent allergens eliciting PACD, and there was a decrease in PACD caused by fragrances. The number of reactions to medications increased. This Study also demonstrated that pesticides can be a cause of PACD. The detection of reactions to Fentichlor was unexpected and, although they have been attributed in some Studies to cross-reactions to sulfanilamides and bithionol, Such a robust association was not observed in this Study. This Study extends Our experience of the changes in the allergens that elicit PACD to 20 years. (J Am Acad Dermatol 2010;62:605-10.)