Købner reaction induced by photodynamic therapy using delta-aminolevulinic acid. A case report.

We report a case of psoriasis reactivation following photodynamic therapy with delta-aminolevulinic acid. An 84-year-old women received several UVB treatment sessions because of severe psoriasis at her crura in the period from 1960 to 1990. Since then her psoriasis had been inactive. In 1994 she was admitted to our out-patient clinic because of multiple dysplastic lesions as well as multiple carcinomas at her crura. Surgical intervention was impossible and retinoids were not tolerated. She was treated with photodynamic therapy, which provoked a Købner reaction followed by a severe reactivation of the otherwise inactive psoriasis. Whether photodynamic therapy is used for the treatment of multiple dysplastic lesions in a psoriasis patient or for the treatment of psoriasis it seems important to be aware of this adverse effect. This is the first report of Købner reaction following photodynamic therapy.