2025. Safety and Efficacy of Photodynamic Therapy with Aminolevulinic Acid 10% Topical Gel Activated by Red Light versus Aminolevulinic Acid 20% Topical Solution Activated by Blue Light for the Treatment of Actinic Keratosis on the Upper Extremities: A Blinded Randomized Study. SKIN The Journal of Cutaneous Medicine. 9, 6 (Nov. 2025), s684. DOI:https://doi.org/10.25251/9sm0xp66.