[Side effects of topical photodynamic therapy].

Photodynamic therapy (PDT) is gaining increasing significance in the treatment of skin cancers and precancerous lesions. Most of the studies dealing with this procedure focus on efficacy. Whereas treatment results are a decisive parameter, before any therapy is accepted the evaluation should also consider side effects in daily practice. We treated 2031 patients with PDT between 2001 and 2006, and evaluated the side effects during and after treatment with a specially designed protocol. The most prominent side effect was pain, which occurred in 92% of patients, followed by erythema/edema (89%) and scaling in conjunction with itching (80%). Less common unwanted effects included crusting (9%), pustules (6%), large erosions (1.2%), pigmentary changes (1%) and infections (0.4%). Especially widespread erosions and pustules caused significant anxiety for the patients. Patients should be informed in detail about the side effects of PDT prior to treatment, since most of the unwanted effects are easily managed, heal without scarring and do not influence the therapeutic response.