Hidradenitis Suppurativa
Clinical guidelines for managing chronic inflammatory skin conditions, evaluating follicular occlusion and TNF-α/IL-17 cytokine cascades, and reviewing biologics and surgical deroofing.
🧠 Standard of Care & Hurley Staging
Hidradenitis Suppurativa (HS), also known as acne inversa, is a painful, chronic, debilitating inflammatory skin condition that primarily affects intertriginous skin folds.
- Presentation: Key cutaneous features.
- Painful Nodules & Abscesses: Deep-seated, extremely tender, inflamed nodules that form in skin-on-skin friction areas (e.g., axillae, groin, perineum, inframammary folds, buttocks).
- Subcutaneous Sinus Tracts: Recurrent abscesses rupture and connect beneath the skin surface, forming epithelialized **draining tunnels (sinus tracts)** that leak foul-smelling purulent fluid.
- Tombstone Comedones: Multi-headed, paired comedones ("double-headed blackheads") in affected skin folds.
- Hypertrophic Scarring: Chronic inflammation leads to dense, rope-like keloidal scars that can restrict physical mobility in the shoulders or groin.
The Hurley Staging System
HS severity is classified clinically using the Hurley Staging system to guide medical and surgical treatment:
| Hurley Stage | Clinical Description |
|---|---|
| Stage I | Single or multiple isolated abscess formation, without sinus tract (tunnel) formation or scarring. |
| Stage II | Recurrent, widely separated abscesses with sinus tract formation and localized scarring. |
| Stage III | Diffuse or near-diffuse involvement across an entire anatomical region, with multiple interconnected sinus tracts and widespread scarring. |
🧬 Diagnostics & Follicular Occlusion Pathophysiology
Diagnosis is clinical, based on lesion type, location, and chronicity (recurrent lesions twice in 6 months). High-frequency ultrasound (HFUS) is used to map subcutaneous tunnel pathways before surgery.
Pathophysiology of Follicular Rupture
The tissue damage and chronic drainage in HS are driven by hair follicle occlusion and subsequent intense immune activation:
- Follicular Occlusion: The primary event is **follicular hyperkeratosis** within the pilosebaceous-apocrine unit. Keratin plugging blocks the hair follicle opening, leading to ductal dilation and swelling.
- Follicular Rupture: Under mechanical friction, the dilated follicle ruptures, releasing keratin, sebum, apocrine sweat, and commensal bacteria (like *Cutibacterium acnes*) into the surrounding dermis.
- Cytokine Cascade (TNF-α, IL-17): The spilled material triggers a massive foreign-body immune response. Infiltrating neutrophils and macrophages release high levels of **Tumor Necrosis Factor-alpha (TNF-α)** and **Interleukin-1β (IL-1β)**. Th17 cells release **Interleukin-17 (IL-17)**, recruiting more inflammatory cells, causing tissue liquefaction (abscesses), and driving the growth of epithelialized sinus tracts.
💊 Biologics & Surgical Interventions
Management requires a combination of anti-inflammatory medications for active disease and surgery to remove chronic sinus tracts.
Medical Management
- Topical & Oral Antibiotics: Mild disease (Stage I) is treated with topical **Clindamycin 1%** solution. Moderate disease (Stage II) is managed with oral tetracyclines (Doxycycline) or a combination of **Clindamycin (300 mg BID) and Rifampicin (600 mg daily)** for 10-12 weeks.
- Biologic Therapies (Anti-TNF & Anti-IL-17): For moderate-to-severe disease (Stage II/III), **Adalimumab** (Humira, anti-TNF) is the primary FDA-approved biologic. **Secukinumab** (Cosentyx, anti-IL-17A) is approved as a second-line biologic for patients who do not respond to anti-TNF therapy.
Surgical Management
- Deroofing: For chronic Hurley Stage II sinus tracts, surgical **deroofing** is performed. The top roof of the tunnel is removed, the tract is scraped clean (curettage), and the wound is left to heal by secondary intention, preserving surrounding healthy tissue.
- Wide Local Excision: For diffuse Hurley Stage III disease, wide surgical excision of the entire affected area is required to prevent recurrence, followed by skin grafting or secondary healing.
🔬 Active Clinical Trials
Clinical trials are currently evaluating next-generation oral Janus Kinase (JAK) inhibitors, anti-IL-17A/F biologics, and laser-assisted surgical deroofing.
A Phase III study investigating if daily oral upadacitinib suppresses multiple cytokine pathways (IL-6, IFN-γ) to reduce active inflammatory nodule counts.
Key Inclusion: Age ≥ 18, moderate-to-severe HS (Hurley Stage II or III), and inadequate response to oral antibiotics.Evaluating if dual inhibition of IL-17A and IL-17F with bimekizumab provides superior clearing of draining tunnels compared to selective IL-17A blockers.
Key Inclusion: Age ≥ 18, moderate-to-severe HS, and failed or intolerant to at least one anti-TNF biologic.Comparing post-operative pain, healing times, and recurrence rates between CO2 laser deroofing and traditional scalpel surgery for Hurley Stage II tracts.
Key Inclusion: Age ≥ 18, at least two active draining sinus tracts in axillae or groin, and candidate for local surgical intervention.🗺️ Next Steps After Diagnosis
If you have recently been diagnosed with Hidradenitis Suppurativa, establish these clinical care pathways:
- Determine Your Hurley Stage: Consult a dermatologist to staging your disease (Stage I, II, or III) to select the correct treatment pathway.
- Discuss Biologic Options Early: If you have recurrent draining tunnels (Stage II/III), discuss anti-TNF (Adalimumab) or anti-IL-17 (Secukinumab) therapies early to prevent progressive scarring.
- Incorporate Antiseptic Washes: Begin using chlorhexidine gluconate (Hibiclens) or benzoyl peroxide wash daily to reduce skin bacterial load.
- Minimize Friction: Wear loose-fitting, breathable cotton clothing and avoid tight undergarments that rub against skin folds.
❓ Patient FAQ
Q: Is Hidradenitis Suppurativa caused by poor hygiene?
A: No. HS is **not** caused by poor hygiene, and it is not contagious. It is an inflammatory condition driven by hair follicle occlusion, genetic factors, and an overactive immune response. It cannot be washed away, and patients should avoid aggressive scrubbing, which can worsen inflammation.
Q: What is the difference between an HS nodule and a regular boil?
A: A regular boil (furuncle) is a simple bacterial infection of a hair follicle that resolves with standard antibiotics and does not recur in the same spot. HS nodules are chronic, recurring in the same areas, and eventually connect under the skin to form draining tunnels (sinus tracts). Antibiotics in HS are used for their anti-inflammatory properties, not just to clear bacteria.