Allergic contact dermatitis caused by cetearyl isononanoate in a sunscreen product.

A 2-year-old boy with a history of atopic dermatitis presented with acute dermatitis on the areas where he had applied the sunscreen product Avène spray® 50+ (Eau Thermale Avene, Avène, France). The reaction, which had started to appear 10min after he had applied the cream, was described as “sunburn”. It lasted for a few days, and improved with corticosteroid cream application. Patch tests were performed on the patient’s back with the European baseline series (ChemotechniqueDiagnostics, Vellinge, Sweden) and his own cosmetics ‘as is’, with Haye® test chambers (Haije Service, Alphen aan den Rijn, TheNetherlands), and two readingswere performed, on day (D) 3 and D4. There was a positive reaction only to the sunscreen product (+++/+++). Subsequent patch testswere performedwith the ingredients of the sunscreen product kindly provided by the manufacturer, diluted in pet. at the same concentrations as used in the sunscreen product. Prick tests with immediate readings were also performed with the sunscreen product and with all the ingredients provided, specifically prepared for prick testing. The only positive patch test reaction (+++), on D3,