Photoallergic contact dermatitis from ketoprofen in southern Sweden

The non-steroidal anti-inflammatory drug ketoprofen is widely used for topical treatment. In Sweden, ketoprofen has been available for topical application since 1995. Photoallergic contact dermatitis from ketoprofen-containing topical preparations usually includes severe eczematous reactions. Ketoprofen is derived from propionic acid, and it is also a substituted benzophenone and therefore structurally similar to fenofibrate and sunscreen agents based on benzophenones. During the last 2 years, 35 patients have been refereed to our department with suspected photoallergic or allergic reactions after having used ketoprofen-containing gels. Photopatch testing with the photopatch standard series, the ketoprofen-containing gels and their ingredients, fenofibrate, benzophenone-3, benzophenone-10 and benzophenone-4, was performed. Photoallergic reactions to ketoprofen were noted in 35 patients and a simultaneous contact allergy to ketoprofen in 2 patients. Simultaneous photoallergy to fentichlor, tetrachlorosalicylanilide and fenofibrate was registered in 74%, 40% and 73% of the patients, respectively.