Histopathologic study of hidradenitis suppurativa following long-pulsed 1064-nm Nd:YAG laser treatment

Abstract

Objective: To assess clinical and histopathologic changes occurring after long-pulsed 1064-nm Nd:YAG laser treatment of hidradenitis suppurativa (HS).

Design: Prospective, controlled clinical and histologic study of patients with Hurley stage II HS disease.

Setting: Outpatient dermatology department at Henry Ford Hospital, Detroit, Michigan.

Participants: Nineteen patients with Fitzpatrick skin types II to VI with Hurley stage II HS lesions of the axilla and groin. Interventions Two monthly laser sessions were performed using the long-pulsed 1064-nm Nd:YAG laser. Main Outcome Measure Clinical response was scored using the modified Sartorius scale for HS reflecting Lesion Area and Severity Index (LASI). Histologic changes were examined before treatment and 1 week, 1 month, and 2 months after treatment.

Results: The percentage change in HS severity after 2 sessions of laser treatment was -31.6 over all anatomic sites (P < .005), -24.4 for the axillary site (P = .008), and -36.8 for the inguinal site (P = .001). Histologic changes corresponded to clinical response. Findings from serial biopsy specimens showed increased inflammation at 1 week after treatment and decreased inflammation with resulting fibrosis and scarring at 1 month and 2 months after treatment.

Conclusions: The long-pulsed 1064-nm Nd:YAG laser is a novel effective treatment option for HS. Our histopathologic data suggest that HS is primarily a follicular disorder. The Nd:YAG laser penetrates for selective photothermolysis of the follicular unit and destruction of organized inflammatory lesions in the superficial to mid dermis. Our study offers insight into the pathogenesis of HS and the mechanism of the Nd:YAG laser in treatment of patients with this chronic, debilitating disease.