Two-step photodynamic therapy for facial acne: a randomized controlled trial of pain reduction with 630 nm red light laser.

Abstract

Although topical 5-aminolevulinic acid photodynamic therapy (5-ALA PDT) is an effective treatment for facial acne, many patients report significant pain during the irradiation phase, compromising adherence. Two-step PDT, which modifies irradiance in two phases, has been proposed to reduce pain without compromising treatment efficacy. In this single-center, assessor-blinded randomized trial, 26 patients with facial acne were allocated to either a two-step PDT group (n = 12) or a conventional PDT group (n = 14). After applying 20% 5-ALA for 2 h, both groups received red light (630 ± 5 nm) to deliver a total fluence of 120 J/cm². In the two-step group, treatment began at 40 mW/cm² for 5 min, then increased to 100 mW/cm² for 18 min. In the conventional group, irradiance was set at 100 mW/cm² for 20 min. Pain was measured using the Numerical Rating Scale (NRS) at 6, 12, 18, 24, and 30 min after initiation of irradiation. Clinical efficacy, adverse events, recurrence, and patient satisfaction were also evaluated. All 26 patients completed three PDT sessions. Pain scores were significantly lower in the two-step group at every time point (p < 0.05). Both groups had comparable clinical efficacy, recurrence rates, and satisfaction levels (p > 0.05). Adverse events were less frequent in the two-step group but did not differ statistically from the conventional group. Two-step PDT using 5-ALA and 630 nm red light laser substantially reduces pain during acne treatment while maintaining equivalent clinical efficacy, recurrence rates, and patient satisfaction. This modified protocol may improve patient tolerance and adherence to PDT.