Makindo Medical Notes

Hidradenitis Suppurativa (HS), also called Acne inversa, is a chronic, relapsing inflammatory skin condition that affects apocrine gland–bearing areas such as the axillae, groin, perineum, buttocks, and under the breasts. It is characterised by painful nodules, abscesses, sinus tract formation, and scarring. Prevalence is estimated at 1–4% of the population.

🔎 About

• Consider HS if a patient has recurrent painful lumps/abscesses in axillae or groin.
• Onset typically after puberty, with progressive chronic inflammation.
• Lesions often begin as pimple-like bumps or inflamed hair follicles.
• Can lead to sinus tracts, scarring, and significant psychosocial impact.

⚠️ Risk Factors

• Female sex (≈3:1 ratio compared to men).
• Family history of HS (autosomal dominant inheritance described).
• Obesity and insulin resistance/metabolic syndrome.
• Smoking (strongest modifiable risk factor).
• Associated conditions: Crohn’s disease, psoriasis, polycystic ovarian syndrome (PCOS), Down’s syndrome.
• Certain drugs: lithium, sirolimus, biologics (rare).

🧬 Aetiology & Pathogenesis

• Not a primary infection — it is an inflammatory follicular occlusion disorder.
• Follicular occlusion → rupture → intense immune response with neutrophils and cytokines (TNF-α, IL-17, IL-1β).
• Secondary bacterial colonisation (Staphylococcus aureus, anaerobes) worsens inflammation but is not the root cause.

👀 Clinical Features

• Painful nodules, abscesses, and sinus tracts with purulent discharge.
• Open double-headed comedones are a clinical hallmark.
• Common sites: axillae, inframammary folds, groin, perineum, buttocks.
• Chronic cases → scarring, contractures, and malodorous drainage.
• Flares may be linked with menstrual cycle; often improve in pregnancy.

📊 Hurley Staging (Severity)

• Stage I: Recurrent nodules or abscesses, no scarring or sinus tracts.
• Stage II: Recurrent abscesses with sinus tracts and scarring, multiple widely separated lesions.
• Stage III: Diffuse or near-diffuse involvement with interconnected sinus tracts and abscesses across entire areas.

🔬 Investigations

• Diagnosis is clinical – recurrent, typical lesions in typical sites.
• Consider swabs to rule out superinfection.
• Screen for metabolic syndrome, diabetes, thyroid disease.
• Consider colonoscopy if coexisting Crohn’s suspected.

💊 Management

• Lifestyle: weight loss, smoking cessation, reduce friction/heat, loose cotton clothing.
• Skin care: antibacterial washes (chlorhexidine/benzoyl peroxide), avoid deodorants that irritate.
• Mild (Hurley I):
  • Topical clindamycin 1% BD (first-line).
  • Oral tetracyclines (doxycycline, lymecycline) for 12 weeks if inadequate response.
• Moderate (Hurley II):
  • Combination therapy: oral clindamycin + rifampicin for 10–12 weeks.
  • Intralesional corticosteroids for acute flares.
  • Hormonal therapy in women (anti-androgenic COC with drospirenone, or spironolactone).
• Severe (Hurley III):
  • Biologics: Adalimumab is NICE-approved for severe HS refractory to standard therapy.
  • Alternative biologics: infliximab, secukinumab (IL-17 inhibitor, EADV 2023 guidance).
  • Surgical options: deroofing of sinus tracts, local excision, or wide excision with grafting in extensive disease.
• Supportive: pain control, psychological support, referral to dermatology specialist clinic.

⚠️ Complications

• Scarring, contractures, disfigurement.
• Restricted mobility and disability.
• Recurrent infections, cellulitis, lymphoedema.
• Rarely: squamous cell carcinoma in chronic HS sinus tracts.
• Profound psychosocial impact: depression, anxiety, social isolation.

📚 References

• DermNet NZ – Hidradenitis suppurativa
• NICE CKS: Hidradenitis suppurativa
• British Association of Dermatologists (BAD) Guidelines