Photopatch tests: an Italian multicentre study from 2004 to 2006.

BACKGROUND: Evaluation of possible photoallergic contact dermatitis in at-risk populations is often not undertaken, and an agreed methodology for investigation is uncommonly used. OBJECTIVES: We conducted a retrospective multicentre study to determine the prevalence of photoallergic contact dermatitis in Italy. METHODS: A total of 1082 patients with histories and clinical features suggestive of photoallergic contact dermatitis were evaluated. All the patients had undergone photopatch testing with allergens proposed for Italy as well as other substances suggested by each patient's personal history. RESULTS: 234 patients (21.6%) were positive to at least one test substance of the standard photopatch testing series or to added substances. 234 patients (21.6%) were positive to at least one substance with a total of 290 reactions. 204 of the reactions were typically photoallergic; 68 reactions were allergic and within this group 10 were photoaugmented reactions; 18 reactions were considered to be phototoxic. CONCLUSION: The predominant group of photoallergens was drugs, followed by organic UV filters and antimicrobial agents.