True photoallergy to sunscreens is rare despite popular belief.

Rising use of sunscreen products has led to increased reporting of adverse reactions to sunscreens. To investigate possible photoallergic reactions in patients who identified themselves as "being allergic" to sunscreens. Patients filled out questionnaires about types of sunscreens they used and timing of their "allergic" reactions. Next, they consented to be photopatch-tested with active sunscreen ingredients, including the new sunscreen Anthelios SX (containing Mexoryl SX) and the new ultraviolet filters Tinosorb M and Tinosorb S. Standard allergen patch testing was also done. Twenty-seven patients self-reported "sunscreen allergy." Photopatch testing is difficult for patients; hence, only 11 agreed to proceed with the testing. Eight patients had negative patch testing results. One patient reacted to benzophenone-2. Another had a prior reaction to titanium dioxide and titanium oxalate but did not react to the silicone-coated titanium in our study. Yet another patient had relevant photopatch reactions to benzophenone-3 and ethylhexyl dimethyl para-aminobenzoic acid (PABA). None reacted to the Tinosorbs or Anthelios SX. Few positive reactions to the standard allergens were not relevant. Although small, this study parallels prior studies in concluding that true delayed type IV hypersensitivity (allergic contact dermatitis and photoallergy) to sunscreens is more infrequent than patients tend to believe.