Tolerability of Photodynamic Therapy Using 10% 5-Aminolevulinic Acid Hydrochloride Gel for Treating Actinic Keratoses on Surface Areas Larger than 75cm.

Photodynamic therapy (PDT) is a well-known treatment modality for actinic keratosis (AK). The largest surface area approved by the FDA is 20cm with 10% 5-aminolevulinic acid hydrochloride gel (10% ALA gel). This retrospective study assessed the tolerability of PDT with 10% ALA gel in areas ranging from 75cm to 300cm. The medical records of 203 patients with AKs treated with 376 PDT sessions using 10% ALA gel were reviewed. Face and ears were incubated with 10% ALA gel for 60 minutes without occlusion while all other areas were incubated for 90 minutes with plastic wrap occlusion followed by 10J/cm blue light. Patients were given specific post-PDT care directions. Patient outcomes data was collected. Skin irritation was reported in 27 (7%) PDT sessions in 25 patients (12%). These occurred primarily on the face (n=17), hands (n=4,) and scalp (n=3). Of the 349 PDT treatments (93%) without irritation, these subjects reported adherence to a specific post-PDT regimen using zinc oxide and healing creams for 48 hours. This was a retrospective study observing safety and tolerability. Clearance data was not collected. Based on this retrospective observational case series, PDT with ALA gel appears to be safe for treating patients with AKs covering surface areas 75 to 300cm. Irritation might be mitigated by post-PDT care regimens.