Red Light Therapy for Hidradenitis Suppurativa: Evidence and Best Devices

TL;DR

• Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition affecting hair follicles in areas where skin rubs together, including the armpits, groin, under the breasts, inner thighs, and buttocks. It causes painful nodules, abscesses, and tunnels that can significantly impact quality of life.
• Red light therapy addresses HS through three relevant mechanisms: reducing the chronic inflammation that drives nodule formation, supporting skin tissue repair and collagen remodelling in affected areas, and improving local microcirculation in tissue that is repeatedly damaged by HS flares.
• Photodynamic therapy (PDT), which combines red light with a topical photosensitizer applied by a dermatologist, has the strongest published evidence for HS. A 2022 systematic review of 18 studies found PDT with ALA effective for 78% to 94% of participants. A 2016 study found 71% of patients maintained remission at 6 months after PDT with methylene blue.
• Standard at-home red light therapy without a photosensitizer has a different and less studied mechanism for HS. The anti-inflammatory and tissue repair effects are directly relevant to HS pathology but the evidence base is earlier stage than for clinical PDT.
• Red light therapy is best approached as a complementary tool alongside medical management of HS, not a replacement for dermatological care, prescribed medications, or clinical procedures.

Hidradenitis suppurativa affects an estimated one in a hundred Australians and remains one of the most challenging chronic skin conditions to manage. The recurrent painful nodules, abscesses, and sinus tracts that characterise HS develop in areas where skin rubs together, primarily the axillae (armpits), groin, inner thighs, under the breasts, and buttocks. Standard management ranges from topical and systemic antibiotics through to biologic medications and surgical intervention, but many people with HS continue to experience flares despite treatment and actively seek complementary approaches to reduce inflammation, manage pain, and support healing between episodes.

Red light therapy has attracted growing interest in the HS community, with both clinical research and patient-reported experience pointing to potential benefits. This guide covers what HS is, how red light therapy addresses its underlying mechanisms, what the research shows, and which devices are most practically suited to treating the anatomical areas most commonly affected.

Understanding Hidradenitis Suppurativa

HS is a chronic inflammatory condition of the hair follicles that is not caused by poor hygiene or infection in the traditional sense. It begins with follicular occlusion, where the hair follicle becomes blocked, leading to rupture of the follicular contents into the surrounding dermis. This triggers a severe inflammatory response that produces the characteristic painful nodules and abscesses. Repeated episodes in the same areas lead to the formation of sinus tracts (tunnels connecting affected areas under the skin) and significant scarring.

HS is staged using the Hurley classification:

• Hurley Stage I: Single or multiple isolated abscesses without sinus tracts or significant scarring. Most responsive to conservative management.
• Hurley Stage II: Recurrent abscesses with sinus tract formation and scarring. Requires more active medical management.
• Hurley Stage III: Diffuse involvement with multiple interconnected sinus tracts and widespread scarring. Typically requires surgical intervention alongside medical management.

The condition disproportionately affects women, people with higher body weight, and smokers, though it occurs across all demographics. The chronic pain, drainage, odour, and scarring of HS have significant impacts on mental health, relationships, and quality of life that extend well beyond the physical symptoms.

How Red Light Therapy Addresses HS Mechanisms

Anti-Inflammatory Effects

Chronic, sustained inflammation is the defining feature of HS. The repeated inflammatory cycles that drive nodule formation, abscess development, and sinus tract extension are fuelled by elevated pro-inflammatory cytokines including TNF-alpha, IL-1beta, IL-6, and IL-17 in affected tissue. Photobiomodulation reduces these cytokines through COX-2 inhibition and macrophage phenotype modulation from pro-inflammatory M1 toward anti-inflammatory M2. Reducing the chronic inflammatory burden in HS-affected areas does not cure the underlying follicular occlusion but addresses the inflammatory amplification that determines how severely each episode progresses and how quickly it resolves.

Tissue Repair and Collagen Remodelling

Repeated HS episodes cause progressive tissue damage including dermal destruction, sinus tract formation, and extensive scarring. Red light at 630 to 660nm stimulates fibroblast activity and collagen synthesis in damaged tissue, supporting the structural repair of the dermis between flares. Improved collagen density and tissue quality may reduce the progression of scarring and support better tissue integrity in repeatedly affected areas.

Improved Local Microcirculation

Nitric oxide released through cytochrome c oxidase activation improves microvascular perfusion in treated tissue. HS-affected areas often have compromised local circulation from repeated inflammatory episodes, scarring, and sinus tract formation. Improved circulation supports oxygen and nutrient delivery to the healing tissue and may support faster resolution of the inflammatory exudate that contributes to abscess formation.

Antimicrobial Effects

Red and near-infrared light have documented antimicrobial effects through reactive oxygen species generation and direct effects on bacterial cell membranes. While HS is primarily an inflammatory rather than infectious condition, secondary bacterial colonisation of HS lesions is common and contributes to the severity and persistence of acute flares. The antimicrobial component of photobiomodulation may be most relevant during active flares where bacterial involvement is contributing to symptom severity.

Photodynamic Therapy vs Standard Red Light Therapy: An Important Distinction

The published evidence for red light therapy in HS is primarily from photodynamic therapy (PDT) rather than standard at-home red light therapy, and understanding the distinction matters for interpreting the research correctly.

Photodynamic Therapy (PDT)

PDT is a clinical procedure where a topical photosensitizer, most commonly 5-aminolevulinic acid (ALA) or methylene blue, is applied to the affected area and allowed to penetrate into the tissue for a set incubation period. The area is then exposed to red light at an appropriate wavelength. The light activates the photosensitizer, generating reactive oxygen species that selectively destroy the abnormal follicular tissue, sebaceous glands, and bacterial populations involved in HS. This targeted destruction mechanism is different from and more aggressive than standard photobiomodulation.

Standard Red Light Therapy

Standard red light therapy without a photosensitizer works through the photobiomodulation mechanisms described above: mitochondrial activation, anti-inflammatory cytokine reduction, collagen stimulation, and improved circulation. This is the mechanism of at-home LED panels and devices. The effects are supportive and anti-inflammatory rather than the targeted tissue destruction of PDT.

Why the Distinction Matters

Most of the strongest published evidence for red light in HS involves PDT performed in clinical settings. The anti-inflammatory and tissue repair benefits of standard photobiomodulation are mechanistically relevant to HS but represent an earlier evidence base specifically for this condition. People using at-home devices should understand that they are accessing the photobiomodulation benefits rather than the full PDT mechanism, and that clinical PDT performed by a dermatologist represents a separate and more potent intervention.

What the Research Shows

Photodynamic Therapy Evidence

A 2022 systematic review published in Photodermatology, Photoimmunology and Photomedicine examined 18 studies on photodynamic therapy for HS. While the review noted that many studies had small sample sizes and methodological limitations including lack of controls and standardisation, the pooled findings showed PDT with ALA was effective for 78% to 94% of participants across the reviewed studies. The review highlighted encouraging results despite the need for more rigorous large-scale trials.

A 2016 retrospective study treated seven HS patients with PDT using methylene blue as the photosensitizer and a 635nm LED light source. Five of the seven participants (71%) maintained remission in the treated area at six-month follow-up, representing a meaningful clinical outcome given the chronic and recurrent nature of HS.

A 2024 study using red light therapy in 16 HS patients found significant improvements in both objective skin measures and participants' quality of life, adding to the body of evidence supporting photobiomodulation for HS management.

The Honest Evidence Position

The evidence for light therapy in HS is promising but not yet at the level of large-scale randomised controlled trials. The 2022 systematic review specifically noted the need for better standardised, controlled studies. Current evidence supports red light therapy as a meaningful complementary approach for mild to moderate HS with relevant anti-inflammatory and tissue repair mechanisms, but it should not be positioned as a primary treatment for moderate to severe disease where dermatological management is essential.

Practical Guidance for Using Red Light Therapy With HS

• Consult your dermatologist before starting. HS management is complex and individual. Your dermatologist needs to be aware of any complementary approaches you are using alongside prescribed treatments.
• Avoid applying directly to open or actively draining lesions. Non-contact treatment from a short distance (2 to 5cm) is more appropriate during active flares. Once lesions have closed, closer contact treatment can be used on the affected area.
• Treat the surrounding tissue as well as the lesion site. The inflammatory component of HS extends beyond the visible lesion into the surrounding dermis. Treating a broader area around active or healing lesions addresses the wider inflammatory environment rather than just the visible nodule.
• Daily sessions during flares, maintenance sessions between flares. The anti-inflammatory effects are most relevant during active episodes. Between flares, three to four sessions per week in previously affected areas supports tissue repair and may help reduce flare frequency over time.
• Avoid heat settings on active inflamed lesions. The thermal comfort settings on wearable devices are beneficial for stiff joints and muscle pain but should not be applied at high settings directly over acutely inflamed HS nodules. Use red and NIR light without elevated heat during active flares.
• Consistency over weeks to months is required to assess meaningful benefit. The anti-inflammatory and tissue repair mechanisms of photobiomodulation are cumulative. Assessing results before eight to twelve weeks of consistent use does not give the treatment adequate time to produce meaningful cumulative change.

StreamShop Devices for Hidradenitis Suppurativa

Red Light Therapy Torch With 900nm: Targeted Precision Treatment

StreamShop's red light therapy torch with 900nm delivers five wavelengths including 660nm and 900nm NIR in a handheld format with four selectable modes. For HS, the torch is the most practical device for reaching the anatomically awkward areas most commonly affected. The axilla, inner thigh, and groin are difficult to treat with panel devices at consistent distance, but the torch can be positioned precisely over individual lesions and surrounding tissue at the appropriate non-contact distance during active flares, and in direct contact once lesions have healed. The 10Hz pulse mode supports pain management during painful flare episodes. The handheld format also allows systematic coverage of the surrounding tissue margin beyond the visible lesion, addressing the broader inflammatory environment.

Red Light Therapy Joint Wrap ($169.99): Conforming Direct Coverage

StreamShop's red light therapy joint wrap at $169.99 delivers 660nm and 850nm at 120 mW/cm² in a flexible wearable format that conforms directly to the body. For HS, the wrap's flexible construction is particularly relevant: it can be positioned over the axilla and upper arm, the inner thigh, and the groin area to deliver consistent hands-free photobiomodulation directly against the skin in HS-affected zones. The wrap maintains close contact over curved and folded skin surfaces where HS most commonly occurs, delivering consistent irradiance without the positioning challenges of handheld devices. Use with the heat settings turned off or at the lowest level (38 degrees) during active inflammatory episodes; heat settings can be used more comfortably during between-flare maintenance sessions.

Portable Red Light Therapy Pad With Near-Infrared: Broader Area Coverage

StreamShop's portable red light therapy pad with near-infrared delivers 660nm and 850nm in a larger flexible wearable format that covers a broader treatment area than the joint wrap. For HS affecting larger zones including the under-breast area, lower abdominal folds, and buttocks, the pad provides hands-free coverage of a more extensive treatment area in a single session position. The flexible design conforms to curved body surfaces and straps in place for consistent contact throughout the session.

Red Light Therapy Belt ($149.99): Full Waistband Area Coverage

StreamShop's red light therapy belt at $149.99 delivers 660nm and 850nm at 120 mW/cm² across 105 dual-chip LEDs in a 126cm x 18cm wireless format. For HS affecting the lower abdomen, groin, and upper inner thigh simultaneously, the belt wraps around the full waistband area to cover the most common lower body HS distribution in a single hands-free session. The wireless power bank compatibility allows sessions during rest without being tethered to a wall outlet. For people with significant lower abdominal and groin HS involvement, the belt provides the most comprehensive simultaneous coverage of this anatomical region available in the device range.

Frequently Asked Questions

Can Red Light Therapy Help With Hidradenitis Suppurativa?

The evidence is promising, particularly for photodynamic therapy performed in clinical settings. A 2022 systematic review found PDT effective for 78% to 94% of HS participants across 18 studies. Standard at-home red light therapy addresses the anti-inflammatory, tissue repair, and circulatory mechanisms relevant to HS through photobiomodulation rather than the PDT mechanism. It is best approached as a complementary tool alongside medical management rather than a primary standalone treatment.

Is Red Light Therapy Safe for HS?

Standard red and near-infrared light therapy is generally safe for use over HS-affected skin. Avoid direct contact with open or actively draining lesions. Treat from a short non-contact distance during active flares and closer contact once lesions have healed. People with HS who are also on immunosuppressant medications or biologics should discuss red light therapy with their dermatologist before starting, as individual circumstances may affect whether it is appropriate alongside their treatment plan.

Can Red Light Therapy Reduce HS Flares?

The anti-inflammatory mechanisms of photobiomodulation are directly relevant to HS flare management. Consistent use may help reduce the severity and duration of flares by lowering the chronic inflammatory burden in affected tissue. Evidence from PDT studies suggests meaningful reductions in active lesion counts and periods of remission, though the at-home photobiomodulation evidence base for flare prevention specifically is earlier stage. Consistent between-flare sessions targeting previously affected areas are the most logical approach for flare reduction rather than reactive use during active episodes only.

What Is the Difference Between PDT and At-Home Red Light Therapy for HS?

Photodynamic therapy (PDT) is a clinical procedure where a topical photosensitizer is applied to HS-affected tissue before red light exposure. The photosensitizer is activated by the light, generating reactive oxygen species that selectively target abnormal follicular tissue and bacteria in a more aggressive way than standard photobiomodulation. At-home red light therapy without a photosensitizer works through mitochondrial activation, anti-inflammatory cytokine reduction, and tissue repair mechanisms. PDT has the stronger published evidence for HS; at-home photobiomodulation addresses relevant mechanisms through a different and more supportive pathway.

Where Should I Apply Red Light Therapy for HS?

Apply to the specific areas where you experience HS involvement: axillae (armpits), groin, inner thighs, under the breasts, and buttocks as relevant to your individual presentation. Treat both the visible lesion site and the surrounding tissue to address the broader inflammatory environment. The torch is most practical for reaching awkward anatomical areas with precision. The joint wrap, portable pad, and belt are most practical for hands-free coverage of the axilla, thighs, and waistband areas respectively.

Should I Use Red Light Therapy During an Active HS Flare?

Yes, with appropriate precautions. During active flares, use non-contact treatment from 2 to 5cm above open or draining lesions to avoid infection risk and wound bed disruption. The anti-inflammatory effects are most relevant during active flares when the inflammatory cascade is driving symptom progression. Avoid elevated heat settings directly over acutely inflamed nodules. Once lesions have closed, closer contact treatment can resume over the healing tissue.