Hidradenitis Suppurativa

Acne Inversa — Chronic, relapsing inflammatory skin disease involving the pilosebaceous unit

Epidemiology

  • Prevalence: ~1–4%
  • Onset: post-puberty, usually 20–40 years
  • Female predominance (≈3:1)
  • Strong association with:
    • Smoking
    • Obesity
  • Positive family history in ~30–40%

Aetiology

  • Follicular occlusion (primary event)
  • Genetic predisposition (autosomal dominant in some families)
  • Hormonal influences (androgens)
  • Environmental factors (smoking, friction)

Pathophysiology

  • Follicular hyperkeratosis → follicular occlusion
  • Follicular rupture → release of keratin and bacteria
  • Intense inflammatory response
  • Abscess formation → sinus tracts and fibrosis

Clinical presentation

Primary Lesions

  • Painful deep-seated nodules
  • Abscesses
  • Purulent discharge
  • Double-ended comedones (pathognomonic)
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Chronic Lesions

  • Sinus tracts
  • Hypertrophic or atrophic scars
  • Fibrosis

Common Sites

  • Axillae (most common)
  • Groin
  • Perineal and perianal regions
  • Inframammary folds
  • Buttocks

🧩 Severity Classification (Hurley Staging)

Stage
Description
Stage I
Abscesses without sinus tracts or scarring
Stage II
Recurrent abscesses with sinus tracts and scarring
Stage III
Diffuse involvement with interconnected tracts
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Investigations

  • Clinical diagnosis
  • Recurrent lesions in typical locations
  • Chronicity and scarring
  • No specific laboratory test

Management

General Measures

  • Weight reduction
  • Smoking cessation
  • Loose clothing
  • Hygiene and antiseptic washes

Medical Therapy

Severity
Treatment
Mild
Topical clindamycin 1% 2x/day for 12 weeks
Moderate
Oral tetracyclines 500 mg 2x1 for 16 weeks
Severe
Oral clindamycin 300 mg 2x1 + rifampicin 600 mg 2x1 for 10 weeks
Refractory
Biologics (adalimumab)
Hormonal
Antiandrogens in women

Procedural & Surgical Treatment

  • Intralesional corticosteroids
  • Incision and drainage (acute abscess)
  • Laser therapy (Nd:YAG)
  • Wide surgical excision (definitive)