Hidradenitis Suppurativa

Hidradenitis suppurativa (HS, or acne inversa) in general practice: recognition, staging and management.

Clinical presentation

HS is a chronic inflammatory disorder of apocrine gland-bearing skin — typically the axillae, groin, perianal region, buttocks and inframammary folds — causing persistent, deep-seated, painful nodules and abscesses that can progress to sinus tracts, purulent discharge and scarring. It usually presents after puberty, in the second to third decade, and is around three times more common in women, though perianal disease is more common in men. A third of patients have an affected first-degree relative. Obesity and smoking are both risk factors, plausibly through skin-fold friction/chronic inflammation and impaired wound healing/follicular occlusion respectively.

HS is not an infection and is not caused by poor hygiene — say this to every patient at diagnosis, since it is routinely mistaken by patients (and sometimes clinicians) for recurrent boils.

Associated comorbidities worth actively screening for: metabolic syndrome, type 2 diabetes, cardiovascular disease, PCOS, depression/anxiety and suicidal ideation, and other immune-mediated disease (inflammatory bowel disease, spondyloarthropathy).

Diagnosis

Diagnosis is clinical, based on all three of: typical lesions (nodules, abscesses, sinus tracts, fibrotic scars), typical distribution (intertriginous areas), and recurrence/chronicity (2 or more episodes over 6 months). A positive family history supports the diagnosis; a negative microbiology swab of affected skin is expected and doesn’t argue against it. Biopsy and imaging are not routinely needed — reserve biopsy for atypical features raising concern for squamous cell carcinoma, a rare but recognised complication of long-standing HS.

Differentials: staphylococcal skin infection (abscess, carbuncle, furuncle), Bartholin or epidermoid cyst, and cutaneous or anogenital Crohn disease.

Staging

Hurley staging is the most widely used clinical scale and guides referral:

• Stage I — single or multiple abscesses without sinus tracts or scarring.
• Stage II — recurrent abscesses with sinus tracts and scarring.
• Stage III — diffuse or multiple interconnected sinus tracts and abscesses across the entire area.

Hurley staging only moves in one direction — once scarring has occurred, the stage cannot be downgraded even with successful medical treatment. Stage II–III disease should prompt referral to dermatology, not an extended trial of primary-care management alone.

General measures

• Educate and reassure: chronic inflammatory condition, not infectious, not due to poor hygiene.
• Smoking cessation.
• Weight management — a GLP-1 agonist is worth considering if the patient is obese, particularly with metabolic comorbidities.
• Absorbent, atraumatic dressings for draining lesions.
• Analgesia: paracetamol/NSAIDs first-line; opioids used cautiously; anticonvulsants or antidepressants for a neuropathic pain component.
• Pruritus: topical corticosteroids or a first-generation oral antihistamine.

Medical treatment

Topical, for mild disease or as an adjunct: clindamycin 1% lotion/gel/ cream twice daily. Topical antiseptics (e.g. 4% chlorhexidine) are widely used but weakly evidenced.

Intralesional: triamcinolone acetonide 10–40 mg/mL injected into an individual inflammatory lesion, repeated weekly to three-monthly.

Oral antibiotics — a short course treats a superimposed bacterial infection; a longer course is used for HS itself for its immunomodulatory effect, not as antimicrobial therapy for infection:

• Mild–moderate disease (Hurley I/II): a single tetracycline — doxycycline 100 mg once or twice daily, minocycline 100 mg twice daily, or equivalent — assessed for response at 12 weeks.
• Severe disease (Hurley III), or tetracycline failure/intolerance at 12 weeks: clindamycin 300 mg twice daily plus rifampicin 300 mg twice daily for up to 12 weeks (reduce to 150 mg dosing, or clindamycin alone, if not tolerated).
• Severe flare unresponsive to the above, or as a bridge to surgery: IV antibiotics — this is a specialist-directed decision, not a primary-care one.

Biologics (adalimumab and others) are reserved for inadequate response to the measures above and are a dermatology-initiated treatment.

Procedures

• Incision and drainage of an acute abscess gives quick relief but has a very high recurrence rate — it is symptom control, not definitive management. See Abscess Incision & Drainage for technique.
• Deroofing, wide local excision and radical excisional surgery are progressively more definitive options for persistent nodules, abscesses and sinus tracts, all specialist procedures with wound-closure and recurrence trade-offs to discuss before referral.

Follow-up

HS is a chronic, scarring condition; spontaneous improvement can occur over time (including after menopause) but established scarring persists.

Early diagnosis and treatment limit lasting damage — the practical argument for referring Stage II–III disease promptly rather than exhausting primary-care options first.