Hidradenitis Suppurativa (HS)

🔍 When to Suspect

Recurrent painful nodules, abscesses, and draining sinus tracts in intertriginous areas (axillae, groin, inframammary) with scarring

From the full topic in The Ocean Library: Hidradenitis Suppurativa (HS)

🧭 When to suspect

Suspect hidradenitis suppurativa (HS) in any patient with recurrent, painful, deep-seated nodules, abscesses and discharging sinus tracts (tunnels) in the skin folds. It is a chronic inflammatory disease of follicular occlusion – not an apocrine gland infection, not contagious, and not caused by poor hygiene – affecting the apocrine-gland-bearing, intertriginous (skin-on-skin) sites: the axillae, groin, perianal and perineal region, inframammary folds, buttocks and genitals.

The diagnosis is clinical and rests on a triad: typical lesions + typical sites + chronicity and recurrence (classically two or more lesions in six months). A near-pathognomonic clue is double-ended “tombstone” comedones alongside rope-like scarring. HS affects roughly 1% of the UK population (estimates 1–4%), shows a female predominance (3:1), and is strongly linked to smoking and obesity. The average delay to diagnosis is 7–10 years, so the key primary-care skill is simply recognising it rather than treating each flare as an isolated “boil”.

Severity is graded with the Hurley staging system, which is recorded per affected site and drives the referral pathway.

Hurley stage	Defining features	Usual setting
I (mild)	Single or multiple abscesses, no sinus tracts or scarring	Usually managed in primary care
II (moderate)	Recurrent abscesses, widely separated lesions, with sinus tracts and scarring	Refer to dermatology
III (severe)	Diffuse involvement with multiple interconnected tracts and abscesses across a whole area	Urgent dermatology referral

⚠️ Common pitfall Treating recurrent HS as a series of unrelated “boils”. Repeated short antibiotic courses and incision & drainage relieve the immediate lesion but miss the diagnosis, and the disease quietly progresses to irreversible sinus tracts and scarring over years. The giveaway is recurrence at the same flexural sites with scarring and double-ended comedones – pattern and chronicity, not the single lesion, make the diagnosis.

Source: British Association of Dermatologists · DermNet

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