Treatment of hidradenitis suppurativa by photodynamic therapy with aminolevulinic acid: Preliminary results

Background: The current standard of care for hidradenitis suppurativa (HS) includes antibiotics (oral/topical), retinoids (oral/topical) and intralesional steroids and is unsatisfactory. Photodynamic therapy (PDT) with 20% 5-aminolevulinic acid (ALA) has been used "off label" to treat acne vulgaris and may hold promise as a therapy for HS. This open-label, non-blinded study investigated the efficacy and safety of ALA PDT for the treatment of HS using two blue light sources and intense pulsed light (IPL) for photoactivation. Methods: Twelve subjects with active HS enrolled to undergo ALA PDT once weekly for four weeks with follow-up visits 4, 8, and 12 or more weeks later. Nine subjects completed the study through the week 8 follow-up visit. Lesions were counted at each treatment visit at week 4, week 8 and at the final week. Results: Mean lesion counts were 11.25 at baseline, 6.5 at 4 weeks (50.8% reduction), and 7.5 at 8 weeks (29.9% reduction). Mean Global Severity Scores were 2.2 at baseline, 1.5 at 4 weeks, and 1.8 at 8 weeks. Mean DLQI scores were 17.3 at baseline, 13.1 at 4 weeks (27.2% improvement), 14.00 at 8 weeks (19.3% improvement) and 14.0 (19.3% improvement) at the final week (16-62 weeks). Three subjects (25%) had complete clearance and no active lesions 4 weeks after the final treatment. Treatments were more tolerable for subjects treated with blue light than with IPL. Conclusion: ALA PDT may be a safe and effective treatment of hidradenitis suppurativa.