Safety and Efficacy of Photodynamic Therapy with ALA 10% Topical Gel Activated by Red Light versus ALA 20% Topical Solution Activated by Blue Light for the Treatment of Actinic Keratosis on the Upper Extremities: A Blinded Randomized Study . J of Skin. 2024;8(6):s485. doi:10.25251/skin.8.supp.485