Green light is effective and less painful than red light in photodynamic therapy of facial solar keratoses

Photodynamic therapy (PDT) with topically applied δ‐aminolevulinic acid (ALA) is increasingly employed to treat patients with multiple solar keratoses and superficial skin tumors. For these indications, ALA‐PDT has been shown to be highly efficient. Treatment of multiple or extended lesions, however, is substantially hampered by the fact that ALA‐PDT is associated with burning pain during the irradiation procedure. The standard irradiation devices commonly used for ALA‐PDT emit red light around 630 nm. In the present half‐side comparison study we have observed that ALA‐PDT employing a green light irradiation device (543–548 nm) is equally effective, as compared with standard red light ALA‐PDT. In contrast to red light ALA‐PDT, however, green light ALA‐PDT caused only little tingling and burning but no pain. These observations indicate that green light ALA‐PDT is superior to standard ALA‐PDT, because it is associated with less unwanted side effects.