Hidradenitis suppurativa staging and care

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

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.

Key points

Diagnosis rests on typical lesions, typical flexural sites and chronic recurrence: painful nodules, abscesses, tunnels and scars in axillae, groins, inframammary, abdominal-fold, genital, perianal or buttock skin.
Ask whether there have been at least two episodes in six months, but do not let an arbitrary frequency erase a convincing longer recurrent history.
Hurley I has nodules or abscesses without tunnels and permanent scars; Hurley II has recurrent lesions with separated tunnels or scars; Hurley III has diffuse interconnected disease.
Hurley stage records structural damage, not today’s inflammatory activity, pain or quality of life; include active lesion counts and patient priorities separately.
Hidradenitis is not caused by poor hygiene and is not contagious; use non-stigmatising language when discussing smoking, weight and friction as modifiable associations.
Routine swabbing is unnecessary for a typical inflammatory flare; culture fresh pus when secondary infection, unusual organisms or repeated antibiotic failure is suspected.
Medical treatment can suppress new inflammation, but persistent tunnels and scarred fields often need deroofing or excision for durable local control.
Screen for depression, pain, metabolic and cardiovascular risk, inflammatory bowel symptoms and inflammatory joint disease, and ask about sexual and work impact.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Follicular occlusion susceptibility

Genetic and immune susceptibility promotes occlusion and rupture of terminal hair follicles in flexural skin; approximately one third report an affected family member.

Tobacco association

Smoking is associated with onset and worse activity, but it neither proves causation in an individual nor justifies withholding effective treatment.

Mechanical and metabolic modifiers

Friction, sweating and higher body weight can aggravate disease through mechanical and inflammatory pathways; people of any size can develop severe hidradenitis.

Not hygiene or contagion

Primary disease is inflammatory rather than a consequence of dirt, sexual transmission or inadequate washing, although secondary bacterial infection can complicate open lesions.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Follicular rupture
An occluded follicle dilates and ruptures, releasing keratin and microbes into the dermis and producing a deeply painful inflammatory nodule or abscess.
2
Tunnel formation
Recurrent deep inflammation connects cavities into epithelialised sinus tracts that drain intermittently and resist short courses directed at surface infection alone.
3
Fibrotic remodelling
Repeated healing lays down rope-like scars, contracts flexural skin and can restrict shoulder, hip or genital movement.
4
Systemic inflammatory burden
Persistent cytokine activation associates with metabolic disease, inflammatory bowel disease, spondyloarthritis and depression, supporting whole-person assessment beyond lesion count.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Deep recurrent flexural nodules

Painful subcutaneous lumps recur at friction-bearing flexures and may rupture with malodorous serous or purulent drainage.

Double-ended comedones

Paired black follicular openings over a shared subcutaneous tract are a useful clue to chronic follicular occlusion.

Tunnels and rope-like scars

Palpable cords, multiple drainage points and bridged or contracted scars establish structural progression beyond an isolated abscess.

Necrotising-infection warningRed flag

Rapid perineal progression, disproportionate pain, crepitus, dusky necrosis, confusion or hypotension requires immediate surgical and sepsis management.

Carcinoma warning changeRed flag

A new hard mass, persistent ulcer, bleeding or altered pain in long-standing anogenital disease needs urgent biopsy and specialist review.

Inflammatory comorbidity

Chronic diarrhoea, abdominal pain, swollen joints, inflammatory back pain or severe fatigue can signal associated bowel, rheumatological or haematological disease.

Red flags requiring action

Sepsis physiology, rapidly progressive perineal pain, crepitus, urinary obstruction, uncontrolled bleeding, a chronic ulcer or mass suggesting squamous-cell carcinoma, severe depression or suicidal thoughts requires urgent escalation.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Full-site lesion map and Hurley stageFirst step
Why
Document structural extent and identify areas needing medical or procedural treatment.
Interpretation and limitations
Stage each region by tunnels and scarring, then record active nodules and abscesses separately because Hurley stage does not fluctuate with today's activity.
02
Quality-of-life, pain and mental-health assessment
Why
Quantify consequences that lesion counts miss and identify immediate psychological risk.
Interpretation and limitations
Use a validated tool when helpful, but direct questions about self-harm, function and intimacy determine safety and shared priorities.
03
Bacterial culture of a selected fresh sample
Why
Investigate suspected secondary infection, unusual exposure or repeated antimicrobial failure.
Interpretation and limitations
Routine surface drainage is commonly polymicrobial and does not prove infection; obtain a good specimen before antibiotics and interpret with clinical cellulitis or systemic signs.
04
Metabolic and cardiovascular risk assessment
Why
Detect associated obesity, hypertension, dysglycaemia and dyslipidaemia and support preventive care.
Interpretation and limitations
Select blood pressure, HbA1c and lipids according to individual risk and act on results without presenting weight loss as a cure or treatment condition.
05
FBC, CRP and targeted comorbidity tests
Why
Assess anaemia, systemic inflammation, infection or suspected bowel and joint disease.
Interpretation and limitations
Inflammatory markers do not stage hidradenitis and normal values do not negate severe local disease; investigate symptoms through the relevant pathway.
06
Biopsy of a changing chronic lesion
Why
Exclude squamous-cell carcinoma or another atypical process.
Interpretation and limitations
Sample viable edge and deeper tissue with consent, orientate and label the specimen accurately, and tell histopathology the disease duration and cancer concern.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Simple bacterial abscess or furunculosis

An isolated acute fluctuant lesion without recurrent typical-site nodules, double comedones, tunnels or scars is more likely a conventional abscess.

Cutaneous Crohn disease

Perianal fistulae communicating with bowel, knife-cut fissures, oedema or gastrointestinal symptoms require colorectal and gastroenterology assessment; Crohn disease and hidradenitis may coexist.

Pilonidal disease

A midline natal-cleft pit and sinus has a different anatomical origin, although simultaneous hidradenitis in buttock or groin skin can occur.

Infected epidermoid cyst

A solitary recurring nodule with a central punctum at a non-flexural site suggests a ruptured epidermoid cyst rather than multifocal follicular disease.

Malignancy in chronic disease

A persistent indurated ulcer, mass, exuberant granulation, bleeding or changed pain within long-standing perineal disease requires biopsy for squamous-cell carcinoma.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Limited early diseaseReduce new inflammatory lesionsFirst stepHurley I or limited Hurley II disease has active nodules without an emergency or extensive tunnel field.

1Explain the diagnosis without hygiene blame, reduce friction and traumatic hair removal, offer absorbent non-adherent dressings and create a proportionate pain plan.
2Consider off-label topical clindamycin for localised disease or a twelve-week oral tetracycline for more widespread activity, using an explicit response and stop assessment.
3EscalationReview recurrence, adverse effects, tunnels and scars; escalate early if new structural damage develops rather than repeating acute abscess prescriptions.

02Moderate to severe diseaseCoordinate dermatology and surgeryMultiple regions, recurrent abscesses, tunnels, scars or substantial quality-of-life impairment persists despite suitable conventional therapy.

1Refer to dermatology for phenotype confirmation, systemic options and biologic assessment while addressing pain, wound products, mood and associated disease.
2Discuss deroofing or excision for persistent tunnels and scarred fields; simple incision and drainage is reserved for acute pressure relief because recurrence is common.
3For eligible adults, initiate specialist adalimumab after inadequate conventional systemic therapy and measure the NICE continuation response after twelve weeks.

03Acute dangerous changeSeparate infection or cancer from flareSystemic toxicity, spreading cellulitis, disproportionate pain, perineal necrosis or a chronic changing ulcer or mass is present.

1Use immediate ABCDE and sepsis assessment, inspect the full involved area with consent and call surgery urgently when necrotising infection is possible.
2Obtain blood and appropriately deep microbiological samples without delaying antibiotics or source control in a sick patient.
3Arrange urgent biopsy and dermatology or cancer-pathway review for a persistent indurated ulcer, mass or bleeding change, ensuring histology receives the specific concern.

Key medicines and prescribing safety3 treatments · regimens, roles and cautions

An off-label option for limited superficial inflammatory lesions, used alongside friction, dressing and pain care rather than as tunnel treatment.

Clindamycin 1% topical lotion

Apply a thin film twice daily to clean, dry affected areas for a defined trial according to the agreed off-label hidradenitis plan.

Avoid indefinite exposure, consider previous antibiotic resistance and colitis, stop for significant diarrhoea or irritation, and do not apply deeply into open cavities.

A practical tetracycline option for more widespread active hidradenitis when contraindications have been excluded.

Lymecycline 408 mg capsules

Take one capsule orally once daily for an initial twelve-week off-label anti-inflammatory course, with a documented response and stop review.

Avoid pregnancy, breastfeeding and under 12 years; consider photosensitivity, organ impairment, absorption interactions and intracranial-pressure symptoms, and do not combine with isotretinoin.

A NICE-recommended biologic for adults with active moderate-to-severe disease after inadequate response to conventional systemic treatment.

Adalimumab

Use the hidradenitis-specific licensed induction and maintenance schedule in specialist care; dosing differs from other indications and requires current SmPC verification.

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.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Tunnels and contracture

Interconnected tracts, dense scars and oedema perpetuate drainage and can impair arm movement, walking, sexual function and toileting.

Secondary infection and sepsis

Open lesions can acquire bacterial infection; spreading cellulitis or systemic toxicity is distinct from sterile inflammatory drainage and needs urgent treatment.

Squamous-cell carcinoma

Rare aggressive carcinoma can arise in long-standing anogenital or buttock hidradenitis, particularly when a lesion changes character or fails to heal.

Psychological and social harm

Pain, odour, drainage and stigma can cause depression, suicidal thinking, intimacy difficulty, unemployment and delayed care after previous dismissive encounters.

Anaemia and inflammatory comorbidity

Chronic blood or fluid loss, systemic inflammation, metabolic disease, arthritis and inflammatory bowel disease can add fatigue and treatment complexity.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Record active inflammatory nodules, abscesses, draining fistulae and pain separately from fixed Hurley stage and patient-reported function.
During antibiotic treatment, assess objective lesion change, adverse effects and the intended end date rather than renewing because drainage persists from an established tunnel.
For adalimumab, apply the NICE twelve-week continuation threshold: at least 25% fewer abscesses and inflammatory nodules with no increase in abscesses and draining fistulae.
At follow-up ask about mood, suicidal thinking, sleep, work, intimacy, dressing costs, smoking goals, metabolic risk, bowel symptoms and inflammatory joint symptoms.
Re-examine chronic anogenital or buttock disease for a non-healing ulcer, mass, bleeding or changed pain and maintain a low threshold for biopsy.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Stage is not activity

Hurley III anatomy remains Hurley III on a quiet day, while severe pain can occur in early-stage disease with one acute nodule.

Drainage can be inflammatory

Purulent-looking material from a tunnel does not by itself establish invasive bacterial infection or demand repeated short antibiotic courses.

Incision is not field cure

Opening one tense abscess may relieve pain but leaves the follicular disease and tunnel architecture that drive recurrence.

Language changes access

Explicitly stating that hidradenitis is not caused by dirt counters shame and can make intimate examination and follow-up more acceptable.

Surgery and medicine complement

Anti-inflammatory therapy reduces new lesions while deroofing or excision removes persistent local tunnel structures.

11Common pitfallsFrequent interpretation and management errors.

01
Calling recurrent flexural nodules poor hygiene or simple boils and failing to look for tunnels and double comedones.
02
Using Hurley stage as the only measure of current activity, pain or biologic response.
03
Taking routine superficial swabs and treating every mixed growth despite no cellulitis or systemic infection.
04
Making smoking cessation or weight loss a gate that must be passed before effective medical or surgical treatment.
05
Repeatedly incising the same tunnel opening without offering deroofing, excision or systemic disease control.
06
Missing squamous-cell carcinoma because a changing chronic ulcer is assumed to be ordinary drainage.