1726-nm Laser for Acne Inversa (Hidradenitis Suppurativa)

Hidradenitis suppurativa (HS) is a long-lasting skin condition that causes painful lumps, abscesses, and tunnels in areas such as the armpits and groin. HS begins around the hair follicle; when the follicle becomes blocked and inflamed, new lesions form. Prior clinical studies of lasers that act on the hair follicle have shown improvement in HS symptoms, and a 1726-nm diode laser-designed to selectively heat oil glands within the follicle-has reduced inflammatory lesions in acne with good tolerability across many skin types. This study will test whether a 1726-nm diode laser can safely reduce inflammatory HS lesions in Hurley stage I-II disease. Adults with bilateral (right/left) affected areas will be randomized so that one side receives active laser treatment and the other side receives a sham procedure. Participants will have three treatment sessions over 8 weeks and follow-up through Week 24 while continuing their stable HS medications. The primary outcome is the percent change in abscess and inflammatory nodule counts on the treated side versus the sham side at Week 16. Secondary outcomes include validated HS responder scores, pain, quality of life, flare rate/antibiotic use, and safety. Results may support a non-ablative, follicle-directed option for early HS.

Hidradenitis suppurativa (HS) is a chronic, relapsing inflammatory disorder of the hair follicle characterized by painful nodules, abscesses, and dermal tunnels that cluster in intertriginous sites. Contemporary models place follicular occlusion and rupture of the pilosebaceous unit, rather than primary apocrine disease, at the start of the cascade, with downstream innate/adaptive immune activation (e.g., TNF-α, IL-17/IL-23 axes). This follicle-centric pathogenesis underpins the therapeutic logic for energy-based approaches that target follicular structures to reduce lesion initiation. Multiple controlled studies show that laser/light devices aimed at the folliculo-sebaceous apparatus can improve HS activity, supporting this mechanistic rationale. In a randomized controlled trial (n=22) of long-pulsed 1064-nm Nd:YAG, three monthly sessions reduced HS severity (modified HS-LASI) by \~65% overall at 3 months in treated vs control sites (p\<0.02), with site-specific reductions (inguinal \~73%, axillary \~62%). As the investigators noted, the success of a hair-epilation laser reinforces primary follicular involvement in HS. Beyond Nd:YAG, laser hair-removal (LHR) platforms have also demonstrated efficacy. A randomized controlled trial of 755-nm alexandrite LHR in mild-to-moderate HS showed improvements on validated clinical measures (e.g., HiSCR), with acceptable safety, again pointing to the clinical relevance of follicular targeting in reducing inflammatory lesion burden and flares. Parallel evidence from acne, another follicular occlusion disease, motivates us to investigate 1726-nm (AviClear) sebaceous-selective photothermolysis for HS. Preclinical modeling and in-vivo histology demonstrate that 1726 nm + contact cooling can deliver selective thermal injury to sebaceous glands while sparing surrounding tissue, achieving the canonical endpoint of selective photothermolysis. Clinically, 1726-nm laser studies in acne report significant reductions in inflammatory lesion counts after a short series of treatments, durable improvement at longer follow-up, and favorable tolerability across Fitzpatrick I-VI. Translating this to HS is biologically plausible for Hurley I-II disease, where new nodule formation remains dominated by follicular events rather than extensive sinus tracts. By reducing sebaceous output and follicular activity, 1726-nm treatment may decrease the frequency and intensity of inflammatory nodules/abscesses, complementing stable background medical therapy (e.g., antibiotics, hormones, or biologics targeting TNF-α/IL-17). Importantly, while energy-based surgery (e.g., CO₂ laser deroofing) is effective for chronic tunnels, a non-ablative, follicle-directed device could address earlier lesional biology, potentially lowering flare rates and delaying progression to scarring disease.