1726-nm Laser for Acne Inversa (Hidradenitis Suppurativa)

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.

Inclusion criteria

• Adults 18-60 years; any sex; Fitzpatrick I-VI.
• Clinical HS, Hurley I-II (Investigator confirmed).
• At least one inflammatory nodule in a paired, bilateral region (axilla, groin/inguinal, inframammary, inner thigh, or buttock) within 4 weeks prior to baseline.
• Able to read/speak English/Chinese/Spanish/Vietnamese and sign consent.
• Willing/able to comply with visits, pre/post-care, standardized photography.
• Agree to avoid new HS procedures/therapies in study areas through Week 24.
• No laser contraindication; agrees to shave/clip hair before treatments.
• Optional translational cohort: willing to undergo 4-mm punch biopsy at baseline and Week 16 from the randomized regions (separate consent).

Exclusion criteria

• Hurley III (extensive sinus tracts).
• No qualifying nodule(s) in paired bilateral regions in past 4 weeks.
• Prior device/procedure to target areas within 3 months (chemical peel, dermabrasion, microneedling/RF, other lasers/LBB, cryo/chemo-destruction)
• Had Botulinum toxin in target areas within 3 months or planned during study.
• Had systemic retinoid (e.g., isotretinoin) within 3 months.
• Photosensitizing meds that, in PI's judgment, materially increase risk and cannot be held.
• Pregnancy/breastfeeding/plans to conceive during study.
• Active infection, still healing wounds (investigator judgment) in target areas.
• History of keloids/hypertrophic scars, radiation to target areas, malignancy in target areas, diagnosed immunodeficiency, uncontrolled coagulation disorder or therapeutic anticoagulation that cannot be safely managed.
• Excessive tanning or inability to avoid tanning.
• Any condition (medical/mental) or prisoner status that in PI's opinion compromises safety or adherence.