Red Light Therapy for Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a chronic, painful, and often debilitating skin condition that is notoriously difficult to manage. Patients understandably search for any intervention that might reduce the frequency and severity of flares. Red light therapy is among the treatments being explored, but the evidence base is extremely limited. This page provides an honest assessment of what we know, what we do not know, and whether PBM is worth considering as part of an HS management strategy.

What Is Hidradenitis Suppurativa?

HS is a chronic inflammatory disease of the hair follicles, primarily affecting areas where skin rubs together — the axillae (armpits), groin, buttocks, and under the breasts. It typically begins after puberty and affects approximately 1–4% of the population, with women affected roughly three times more often than men.

The Disease Process

HS begins with follicular occlusion — blockage of hair follicles by keratinous material. The sequence of events that follows is what makes HS so distressing:

1. Follicular plugging — hair follicles become blocked, similar to the process in acne but involving apocrine gland-bearing skin
2. Follicular rupture — the blocked follicle ruptures beneath the skin surface, releasing keratin and bacteria into the surrounding dermis
3. Intense inflammatory response — the immune system reacts to this spillage with a disproportionately aggressive inflammatory cascade involving neutrophils, TNF-alpha, IL-1beta, and IL-17
4. Abscess formation — painful, inflamed nodules and abscesses develop
5. Sinus tract formation — in moderate-to-severe HS, interconnecting tunnels (sinus tracts) form beneath the skin, creating chronic drainage pathways
6. Scarring — repeated cycles of inflammation and healing produce significant scarring and tissue destruction

HS is classified using the Hurley staging system:

• Stage I: Isolated abscesses without scarring or sinus tracts
• Stage II: Recurrent abscesses with sinus tract formation and scarring
• Stage III: Diffuse involvement with multiple interconnected sinus tracts and extensive scarring

Why HS Is So Difficult to Treat

The chronic, relapsing nature of HS means that no single treatment reliably prevents flares. Current management includes:

• Antibiotics (doxycycline, clindamycin/rifampicin combination) — modest efficacy, resistance concerns
• Biologics (adalimumab is the only approved biologic for HS) — effective for some patients but expensive and not universally available
• Surgery — excision of affected tissue, ranging from local deroofing to wide excision. Often the only effective option for Stage II–III disease
• Lifestyle modifications — weight management, smoking cessation, loose clothing

The unmet need in HS treatment is substantial. Many patients cycle through multiple therapies without adequate symptom control.

The Theoretical Basis for Red Light Therapy in HS

Red light therapy has established anti-inflammatory effects that are theoretically relevant to HS:

Anti-Inflammatory Modulation

PBM reduces production of pro-inflammatory cytokines, including TNF-alpha, IL-1beta, and IL-6 (Hamblin, 2017, BBA Clinical, 6:113-124). These are the same cytokines that drive the HS inflammatory cascade. TNF-alpha is particularly central to HS pathophysiology — adalimumab, the only approved biologic for HS, is a TNF-alpha inhibitor.

The fact that PBM modulates the same inflammatory pathway targeted by the most effective drug therapy for HS is noteworthy. However, the degree of TNF-alpha suppression achieved by PBM is far more modest than that produced by a biologic drug, and whether PBM produces clinically meaningful anti-inflammatory effects in the deep dermis and subcutaneous tissue affected by HS is unproven.

Wound Healing

PBM accelerates wound healing through increased fibroblast activity, collagen production, and angiogenesis (Avci et al., 2013, Seminars in Cutaneous Medicine and Surgery, 32(1):41-52). This is relevant to HS because:

• Open wounds and draining sinus tracts are a common feature of moderate-to-severe HS
• Post-surgical healing is an important consideration after HS excision
• Chronic wounds in HS patients often heal slowly due to the inflammatory microenvironment

Antimicrobial Effects

Red and blue light have documented antimicrobial properties. Blue light (405–470 nm) in particular has bactericidal effects through photoexcitation of endogenous porphyrins in bacteria. While HS is not primarily an infectious disease, secondary bacterial colonisation of sinus tracts contributes to flare severity and chronicity.

Dai et al. (2012, Virulence, 3(3):271-282) reviewed the antimicrobial properties of blue and red light and noted that blue light is effective against a range of bacteria found in skin infections, including Staphylococcus aureus — an organism commonly cultured from HS lesions.

What Does the Clinical Evidence Actually Show?

This is where the honest assessment becomes important: direct clinical evidence for red light therapy in HS is extremely limited.

Photodynamic Therapy (PDT) — Related but Different

The most relevant published evidence involves photodynamic therapy (PDT), which uses a photosensitising agent (typically aminolaevulinic acid or methyl aminolaevulinate) applied to the skin, followed by light activation. PDT is a fundamentally different intervention from standalone PBM, as it relies on the photosensitiser to generate reactive oxygen species that destroy targeted cells.

Fadel and Tawfik (2015, Clinical and Experimental Dermatology, 40(4):436-439) investigated topical ALA-PDT in 10 HS patients (Hurley Stage I–II). Treatment consisted of 20% ALA applied to affected areas, followed by activation with 630 nm red light. After 3–4 sessions, 8 of 10 patients showed at least moderate improvement, with reduced nodule count and inflammation scores.

Schweiger et al. (2011) reported a case series of HS patients treated with ALA-PDT, showing variable results. Some patients experienced meaningful improvement; others showed minimal response.

Important distinction: PDT results cannot be attributed to red light alone. The photosensitiser is the active therapeutic agent; the light merely activates it. PDT evidence does not support standalone red light therapy for HS.

Standalone PBM for HS

No published randomised controlled trial has examined standalone red light therapy (without a photosensitiser) for hidradenitis suppurativa. This is the critical fact that must inform any decision about using PBM for this condition.

There are case reports and anecdotal accounts from patients who have incorporated red light therapy into their HS management regimen and reported subjective improvement, but these cannot be distinguished from placebo response, natural fluctuation in disease activity, or the effects of concurrent treatments.

Where PBM Might Reasonably Help in HS

Despite the lack of direct evidence, there are specific scenarios where PBM may offer benefit as an adjunct to standard HS treatment:

Post-Surgical Wound Healing

After surgical excision or deroofing of HS lesions, PBM has a plausible role in accelerating wound healing. The wound-healing evidence for PBM is well-established in other surgical contexts (multiple RCTs), and HS surgical wounds — which heal by secondary intention over weeks to months — could benefit from enhanced fibroblast activity and collagen production.

Protocol suggestion: 630–660 nm red light, 20–40 mW/cm2, 4–6 J/cm2 per session, applied daily to healing surgical sites once the wound is clean and free of active infection.

Pain and Inflammation Between Flares

During periods of low-grade inflammation (Hurley Stage I, with isolated tender nodules but no active abscess formation), PBM’s anti-inflammatory effects may provide modest symptom relief.

Protocol suggestion: 630–660 nm red + 850 nm NIR, 20–40 mW/cm2, 6–10 J/cm2 per session, 3–5 times per week to affected areas.

Scar Management

HS produces significant scarring, and PBM has evidence supporting improved scar quality when applied during the remodelling phase (Carvalho et al., 2010, Journal of Cosmetic and Laser Therapy, 12(2):86-89). For HS patients with established scarring, PBM may improve scar pliability and reduce keloid-like thickening.

What PBM Cannot Do for HS

To set appropriate expectations:

• PBM will not prevent HS flares. The underlying pathological process — follicular occlusion and immune dysregulation — is not addressed by light therapy.
• PBM will not treat active abscesses. Deep, fluctuant abscesses require incision and drainage, often with concurrent antibiotic therapy. Light cannot penetrate deeply enough to sterilise or resolve an established abscess.
• PBM will not replace biologics or surgery for moderate-to-severe HS. These remain the cornerstone treatments for Hurley Stage II–III disease.
• PBM will not eliminate sinus tracts. Established sinus tracts are lined with epithelium and require surgical excision.

Practical Recommendations

If you have HS and want to try red light therapy, a reasonable approach would be:

1. Continue all prescribed HS treatments. PBM should be considered an add-on, not a replacement.
2. Focus on post-surgical healing if you are undergoing surgical management — this is where the evidence is strongest.
3. Use a combination of red (630–660 nm) and near-infrared (830–850 nm) wavelengths to address both superficial inflammation and deeper tissue.
4. Avoid treating actively infected or draining lesions with contact devices. Use a panel device at 6–10 inches distance instead.
5. Track your results objectively. Photograph treated areas monthly and log flare frequency and severity. HS has a naturally fluctuating course, and without objective tracking, it is easy to attribute natural remission periods to whatever treatment you started most recently.
6. Give it an adequate trial. If you see no subjective improvement after 8–12 weeks of consistent use, PBM is unlikely to be providing meaningful benefit for your HS.

The Bottom Line

The theoretical basis for red light therapy in hidradenitis suppurativa is plausible — the anti-inflammatory, wound-healing, and antimicrobial mechanisms of PBM align with aspects of HS pathophysiology. However, the clinical evidence is essentially absent. No controlled trial has demonstrated that standalone PBM improves HS outcomes.

The most defensible use of PBM in HS is as an adjunct for post-surgical wound healing, where the wound-healing evidence from other surgical contexts is directly applicable. For symptom management between flares, PBM is unlikely to cause harm and may provide modest anti-inflammatory benefit, but expectations should be kept very low.

HS is a serious, often severe disease that deserves evidence-based treatment. If you are struggling with HS, prioritise working with a dermatologist experienced in HS management before considering unproven adjunct therapies.