Hidradenitis Suppurativa
Summary
Hidradenitis Suppurativa (HS) is a chronic, painful, debilitating inflammatory skin disease of the hair follicle (not just the apocrine gland). It affects intertriginous areas (Axilla, Groin, Sub-mammary, Perineum). It presents with recurrent nodules, abscesses, and draining sinus tracts leading to "rope-like" scarring. It is strongly associated with Smoking and Obesity, and has a profound impact on quality of life (higher than Psoriasis). Management ranges from lifestyle changes to Biologics (Adalimumab) and radical surgery. [1,2]
Clinical Pearls
The "Boil" Misnomer: Patients are often repeatedly treated for "recurrent balls/boils" with short courses of antibiotics and I&D. This is wrong. HS is an inflammatory disease, not just an infection. Recurrent boils in the axilla/groin = HS until proven otherwise.
Marjolin's Ulcer Risk: Chronic inflammation leads to malignancy. HS patients have a risk of developing aggressive Squamous Cell Carcinoma (SCC) within long-standing sinus tracts. Any rapidly changing or ulcerating lesion needs biopsy.
The "Double Comedone": A blackhead with two or more openings (tombstone comedone). This is pathognomonic for HS.
Demographics
- Prevalence: 1-4%.
- Gender: F > M (3:1).
- Age: Puberty to 40s. Rare after menopause.
Risk Factors
- Smoking: 70-90% of patients are smokers. Major trigger.
- Obesity: Mechanical friction + hormonal effect.
- Microbiome: Dysbiosis.
Mechanism (The Follicular Occlusion Tetrad)
- Follicular Occlusion: Keratin plug blocks the hair follicle.
- Dilatation: Follicle swells and ruptures.
- Inflammation: Contents (keratin/bacteria/hair) spill into dermis -> Massive immune response (neutrophils/TNF-alpha).
- Chronic State: formation of epithelialised tunnels (Sinus Tracts) which constantly drain and reinfect.
(Note: HS is part of the Follicular Occlusion Tetrad: HS + Acne Conglobata + Dissecting Cellulitis of Scalp + Pilonidal Sinus).
Symptoms
- Pain (Severe, shooting).
- Malodorous discharge (pus/blood).
- Social isolation / Depression.
Hurley Classification
Used to guide treatment.
- Stage I: Solitary or multiple isolated abscesses. NO scarring or sinus tracts.
- Stage II: Recurrent abscesses with sinus tracts and scarring. Separated by normal skin.
- Stage III: Diffuse or near-diffuse involvement. Multiple interconnected tracts and abscesses across the entire area.
- Sites: Axillae, Inguinal, Perianal, Inframammary, Buttocks.
- Lesions:
- Inflammatory nodules (deep, red).
- Draining sinuses (express pus on pressure).
- Hypertrophic scarring ("Rope-like" bands).
- Double comedones.
Diagnosis
- Clinical: No specific lab test. "Recurrent painful lesions in flexural sites > 6 months".
- Swabs: Often sterile or show mixed flora. Only useful to rule out MRSA.
- Biopsy: Only if SCC suspected.
Management Algorithm
HIDRADENITIS SUPPURATIVA
↓
LIFESTYLE (Mandatory for all)
- Stop Smoking (Critical)
- Weight Loss
- Loose clothing
- Antiseptic wash (Chlorhexidine)
↓
HURLEY STAGING
┌─────────┴─────────┐
STAGE I STAGE II/III
(Mild) (Mod/Severe)
↓ ↓
TOPICAL / ACUTE SYSTEMIC THERAPY
- Clindamycin - **Lymecycline** (3 months)
(Topical) - **Clindamycin + Rifampicin**
- Intralesional (10 weeks - potent)
Steroids - Dapsone / Acitretin
- Metformin
IF FAILS -> BIOLOGICS
- **Adalimumab** (Humira)
- Secukinumab
↓
SURGERY
- Deroofing (Stage I/II)
- Wide Excision (Stage III)
Medical Therapy
- Antibiotics (Anti-inflammatory dose):
- Tetracyclines: Lymecycline/Doxycycline x 3 months.
- Clinda-Rif: Combination therapy for severe disease.
- Biologics (TNF Inhibitors):
- Adalimumab: Gold standard for moderate-severe HS.
- Hormonal: Anti-androgens (Spironolactone) in females.
Surgical Therapy
- Incision & Drainage: Only for relief of acute painful abscess. HIGH recurrence rate (does not remove the cyst wall).
- Deroofing: Laying open the sinus tract and scraping the base. Good for persisent tracts.
- Wide Local Excision: Removing the entire apocrine skin bearing area. Requires graft/flap. Curative for that specific site.
- Squamous Cell Carcinoma: In chronic anal/gluteal disease.
- Fistulae: Can erode into rectum or urethra.
- Anaemia: Of chronic disease.
- Lymphoedema: Due to scarring of lymphatics.
- Chronic, relapsing course.
- "Cure" is difficult without radical surgery.
- Smoking cessation significantly reduces flare frequency.
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| HS Management | BAD (British Assoc Derm) | Stages of antibiotic escalation. |
| Euro Guideline | EDF (European Derm Forum) | Adalimumab protocols. |
Landmark Evidence
1. PIONEER I & II Trials (NEJM 2016)
- The pivotal trials that led to the approval of Adalimumab for HS. Showed significant reduction in abscess/nodule count compared to placebo.
What is HS?
It is not just "bad acne" or "an infection because of poor hygiene". It is a genetic, inflammatory disease where your own immune system attacks the hair follicles in your armpits and groin.
Why does it smell?
It is not because you are dirty. The inflammation causes tunnels under the skin that trap bacteria and old skin cells. When these drain, they can smell. Special antiseptic washes can help.
The Smoking Link
Smoking is the #1 fuel for this fire. The chemicals in smoke directly block the skin pores. Many patients find their disease "burns out" when they quit smoking.
Treatment
We use long courses of antibiotics (months, not weeks) – not mainly to kill bacteria, but because they calm down inflammation. If that fails, we have powerful injections (Biologics) or surgery to remove the affected skin.
Primary Sources
- Ingram JR, et al. British Association of Dermatologists guidelines for the management of hidradenitis suppurativa. Br J Dermatol. 2019.
- Kimball AB, et al. Adalimumab for the treatment of moderate to severe Hidradenitis Suppurativa (PIONEER). N Engl J Med. 2016.
Common Exam Questions
- Diagnosis: "Double comedones?"
- Answer: Pathognomonic for HS.
- Staging: "Hurley Stage II vs III?"
- Answer: Stage II has normal skin between lesions. Stage III is diffuse scarring with no normal skin.
- Treatment: "Antibiotic combination for severe disease?"
- Answer: Rifampicin + Clindamycin.
- Complication: "New ulcer in chronic HS?"
- Answer: Biopsy to exclude SCC.
Viva Points
- Why Rifampicin?: It penetrates granulomas and biofilm very well. But interacts with CYP450 (render OCP ineffective).
- The psychological burden: HS has the highest suicide risk of any dermatological condition due to pain and shame.
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.