Ultrasound-guided photodynamic therapy with intralesional methylene blue and a 635 nm light-emitting diode lamp in hidradenitis suppurativa: A retrospective study of 41 patients.

ABSTRACT

BACKGROUND: Photodynamic therapy for hidradenitis suppurativa (HS) is a therapeutic alternative with a good safety profile, but its effectiveness has yet to be demonstrated. OBJECTIVES: To demonstrate the effectiveness of PDT with intralesional methylene blue in HS lesions. METHODS: A retrospective cross-sectional study was performed. Forty-one patients were treated with intralesional methylene blue and a diode lamp. Follow-up was carried out at 1 and 6 months after therapy. Efficacy was determined by the diameter reduction of the lesion measured by high-frequency ultrasound. RESULTS: A reduction of ≥75% in the maximum diameter was recorded in 58.5% of the lesions, while 22% showed a reduction between 50% and 75%, and 19.5% showed a reduction of <50%. Recurrence rate was 12.5%. The lesions treated in patients with typical forms of HS (Canoui-Poitrine phenotype I) had a better therapeutic response. No statistically significant differences were found in terms of lesion location or concomitant treatment. CONCLUSION: This therapy may potentially be a cost-effective and well-tolerated local therapy for Hurley I-II patients with superficial abscesses and fistulas.