RESUMEN
BACKGROUND: Photoallergic contact dermatitis (PACD) to oxybenzone was reported for the first time in 1980. Oxybenzone is the most common photoallergen in the United States and Canada and the fourth most common .in Europe. There are no studies or data on the prevalence of oxybenzone PACD in Argentina. OBJECTIVE: To determine the proportion of photosensitive patients with PACD to oxybenzone. METHODS: We conducted a descriptive cross-sectional study of 35 patients with photosensitivity reactions confirmed by photopatch testing at the Research Center of Hospital Público San Martín in La Plata, Argentina, in 2015 and 2016. RESULTS: PACD was identified in 6 patients (17.14%). Five of these (14.28%) had at least one positive reaction to oxybenzone in the photopatch test; 4 had a reaction at irradiated sites only (5 J/cm2 UVA) and one had a reaction at both irradiated and nonirradiated sites. CONCLUSIONS: PACD to sunscreens containing oxybenzone is common and is probably underdiagnosed due to a lack of confirmation by photopatch tests or other diagnostic tools. Sensitization rates vary according to region and are influenced by sunscreen ingredients and variations in the use of sunscreen products, cosmetics, and topical drugs.