Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.
Diagnose hidradenitis suppurativa from recurrent lesions in typical flexures, stage structural damage, identify emergencies and comorbidity, and coordinate medical, wound, pain, lifestyle and surgical care without blame.
Hidradenitis suppurativa is a chronic inflammatory follicular disease, often misdescribed as recurrent boils. Examine every involved site with permission, privacy and a chaperone according to patient preference. Record tender nodules, abscesses, open or closed tunnels, double-ended comedones, drainage, odour and scars. In darker skin, active erythema may be violaceous, grey or difficult to see; tenderness, heat, swelling and drainage remain reliable.
Stage anatomy with Hurley classification, then separately measure current activity and burden. A patient with Hurley I may have intensely painful frequent nodules, while Hurley III can be structurally extensive but temporarily quiet. Ask about dressing use, sleep, movement, continence, intimacy, work and mood. Examine for cellulitis and perineal necrotising infection whenever pain or systemic illness is out of proportion to the usual pattern.
Care is longitudinal and multidisciplinary. Reduce friction, support comfortable absorbent dressings, treat pain, offer tobacco cessation and weight support without making them prerequisites, and use anti-inflammatory medicines according to severity. Drainage of one abscess may relieve pressure but does not cure its diseased follicular field. Dermatology and surgery should coordinate tunnels, biologic eligibility and procedures rather than serially passing the patient between services.
Genetic and immune susceptibility promotes occlusion and rupture of terminal hair follicles in flexural skin; approximately one third report an affected family member.
Smoking is associated with onset and worse activity, but it neither proves causation in an individual nor justifies withholding effective treatment.
Friction, sweating and higher body weight can aggravate disease through mechanical and inflammatory pathways; people of any size can develop severe hidradenitis.
Primary disease is inflammatory rather than a consequence of dirt, sexual transmission or inadequate washing, although secondary bacterial infection can complicate open lesions.
An occluded follicle dilates and ruptures, releasing keratin and microbes into the dermis and producing a deeply painful inflammatory nodule or abscess.
Recurrent deep inflammation connects cavities into epithelialised sinus tracts that drain intermittently and resist short courses directed at surface infection alone.
Repeated healing lays down rope-like scars, contracts flexural skin and can restrict shoulder, hip or genital movement.
Persistent cytokine activation associates with metabolic disease, inflammatory bowel disease, spondyloarthritis and depression, supporting whole-person assessment beyond lesion count.
Painful subcutaneous lumps recur at friction-bearing flexures and may rupture with malodorous serous or purulent drainage.
Paired black follicular openings over a shared subcutaneous tract are a useful clue to chronic follicular occlusion.
Palpable cords, multiple drainage points and bridged or contracted scars establish structural progression beyond an isolated abscess.
Rapid perineal progression, disproportionate pain, crepitus, dusky necrosis, confusion or hypotension requires immediate surgical and sepsis management.
A new hard mass, persistent ulcer, bleeding or altered pain in long-standing anogenital disease needs urgent biopsy and specialist review.
Chronic diarrhoea, abdominal pain, swollen joints, inflammatory back pain or severe fatigue can signal associated bowel, rheumatological or haematological disease.
An isolated acute fluctuant lesion without recurrent typical-site nodules, double comedones, tunnels or scars is more likely a conventional abscess.
Perianal fistulae communicating with bowel, knife-cut fissures, oedema or gastrointestinal symptoms require colorectal and gastroenterology assessment; Crohn disease and hidradenitis may coexist.
A midline natal-cleft pit and sinus has a different anatomical origin, although simultaneous hidradenitis in buttock or groin skin can occur.
A solitary recurring nodule with a central punctum at a non-flexural site suggests a ruptured epidermoid cyst rather than multifocal follicular disease.
A persistent indurated ulcer, mass, exuberant granulation, bleeding or changed pain within long-standing perineal disease requires biopsy for squamous-cell carcinoma.
Interconnected tracts, dense scars and oedema perpetuate drainage and can impair arm movement, walking, sexual function and toileting.
Open lesions can acquire bacterial infection; spreading cellulitis or systemic toxicity is distinct from sterile inflammatory drainage and needs urgent treatment.
Rare aggressive carcinoma can arise in long-standing anogenital or buttock hidradenitis, particularly when a lesion changes character or fails to heal.
Pain, odour, drainage and stigma can cause depression, suicidal thinking, intimacy difficulty, unemployment and delayed care after previous dismissive encounters.
Chronic blood or fluid loss, systemic inflammation, metabolic disease, arthritis and inflammatory bowel disease can add fatigue and treatment complexity.
Hurley III anatomy remains Hurley III on a quiet day, while severe pain can occur in early-stage disease with one acute nodule.
Purulent-looking material from a tunnel does not by itself establish invasive bacterial infection or demand repeated short antibiotic courses.
Opening one tense abscess may relieve pain but leaves the follicular disease and tunnel architecture that drive recurrence.
Explicitly stating that hidradenitis is not caused by dirt counters shame and can make intimate examination and follow-up more acceptable.
Anti-inflammatory therapy reduces new lesions while deroofing or excision removes persistent local tunnel structures.
Calling recurrent flexural nodules poor hygiene or simple boils and failing to look for tunnels and double comedones.
Using Hurley stage as the only measure of current activity, pain or biologic response.
Taking routine superficial swabs and treating every mixed growth despite no cellulitis or systemic infection.
Making smoking cessation or weight loss a gate that must be passed before effective medical or surgical treatment.
Repeatedly incising the same tunnel opening without offering deroofing, excision or systemic disease control.
Missing squamous-cell carcinoma because a changing chronic ulcer is assumed to be ordinary drainage.
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A patient has recurrent painful axillary nodules with several scars and two separated draining tunnels. Normal skin lies between affected areas. Which Hurley stage is most accurate?
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.
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Avoid indefinite exposure, consider previous antibiotic resistance and colitis, stop for significant diarrhoea or irritation, and do not apply deeply into open cavities.
Avoid pregnancy, breastfeeding and under 12 years; consider photosensitivity, organ impairment, absorption interactions and intracranial-pressure symptoms, and do not combine with isotretinoin.
Screen for serious infection and tuberculosis, review vaccination and demyelinating or heart-failure risk, withhold during important infection, and continue only when the specified twelve-week response is achieved.