Whenever possible, patch tests with the patients’ personal sunscreen product used were also performed with the European baseline series (in France, Chemotechnique [Chemotechnique Diagnostics, Vellinge, Sweden], or in Belgium, Trolab [Hermal AG, Reinbeck, Germany]). One child (group A, patient 4) had patch tests only with her own products. The patch test materials used were Haye's Chambers (Haye's Service B.V., Alphen aan den Rijn, the Netherlands) in France, Finn Chambers (Epitest LtdOy,Tuusula, Finland) in France and Belgium, and Van der Bend Chambers (Van der Bend, Brielle, the Netherlands) in Belgium, with 2 readings, the first on day 2 or 3 and the second on day 3 or 4 and sometimes also on day 7. Additional patch tests were performed with the ingredients of the sunscreen products provided by the manufacturers, and every patient underwent patch tests with octocrylene (10% concentration in petroleum) (Chemotechnique). Four children (group A, patients 4 and 8-10) and all adult patients (groups B and C) but 2 (group B, patients 9 and 14) underwent photopatch testing with octocrylene. Patients 6 to 11 and 15 to 28 in group B and all patients in group C but 4 (patients 2-4 and 14) also had photopatch tests with the European baseline photopatch tests series. Patients 1 to 5 (group B) and 2 to 4 and 14 (group C) had photopatch tests with the ingredients of the commercial ketoprofen-containing gel and also benzophenone-3 and fenticlor. Duplicate allergens were applied to the mid-upper back, and 1 set was irradiated on day 1 with 5 J/cm2 of fluorescent UV-A using PUVA 800 Waldmann (Herbert Waldmann GmbH & Co KG, Villingen-Schwenningen, Germany), in France, Alfasun (BLS Light System Products, Wolvertem, Belgium) in Belgium, and Philips Performance UVA 100-W-R lamps (Philips International B.V., Amsterdam, the Netherlands) in France and Belgium. Readings were performed after removal of the control set on days 2 and 3 after irradiation and sometimes also on day 7 after irradiation. According to the criteria of International Contact Dermatitis Research Group, + indicates weak positive reaction with erythema and edema; ++, true-positive reaction with erythema, edema, and vesicles; and +++, strong positive reaction spreading locally with sometimes bullae.