Hidradenitis suppurativa: AU general practice recognition and treatment

Hidradenitis suppurativa (HS) — also called acne inversa — is a chronic, relapsing inflammatory condition of the skin that affects the intertriginous areas where skin surfaces rub together. The axillae, inguinal folds, inframammary creases, perianal, and perineal regions are the most commonly involved sites. Despite its original naming, HS is not primarily a disease of the apocrine sweat glands: the underlying mechanism is follicular occlusion followed by rupture, release of keratin and bacteria into the surrounding dermis, and a cascade of intense localised inflammation that eventually produces sinus tracts and scarring.

HS affects approximately 0.5–1% of Australians, with a female-to-male ratio of about 3:1 in clinical samples and onset most often between ages 15 and 35. The Australasian College of Dermatologists estimates that the average time between first symptoms and correct diagnosis is 7 to 10 years — a delay that results in preventable scarring, progressive disability, and years of undertreated pain. General practitioners encounter HS regularly and are positioned to dramatically reduce that diagnostic gap.

A. Core clinical — the AU general-practice framework

Recognition and history

The clinical pattern of HS is its most reliable diagnostic tool. The history to take includes:

• Sites involved — bilateral involvement in axillae or groin is highly characteristic
• Duration and recurrence — multiple episodes in the same sites over ≥6 months
• Type of lesion — tender nodules and abscesses that do not resolve between episodes; sinus tracts with chronic drainage; rope-like scarring
• Smoking status — the most important modifiable risk factor; ~70% of HS patients smoke
• BMI and metabolic history — obesity, type 2 diabetes, metabolic syndrome
• Family history — approximately 30% have an affected first-degree relative
• Hormonal pattern — premenstrual flares; polycystic ovary syndrome association
• Associated conditions — bowel symptoms (IBD, Crohn’s), joint pain (spondyloarthropathy), mood symptoms
• Impact — pain score, days off work, sexual function, social withdrawal

On examination, the characteristic distribution and the presence of double-headed comedones (a finding specific to HS) help distinguish it from furunculosis, pilonidal disease, or epidermal inclusion cysts. Sinus tract formation and the stellate scarring pattern are seen in more advanced disease.

eTG complete and the Australasian College of Dermatologists recommend comorbidity screening at every HS consultation: depression (PHQ-9), anxiety (GAD-7) with specific inquiry about suicidal ideation, metabolic syndrome, IBD, PCOS, and spondyloarthropathy.

Hurley staging

The Hurley classification is the primary staging system used in AU general practice and guides treatment escalation:

Stage	Description
I	Abscess(es), single or multiple, with no sinus tracts and no scarring
II	Recurrent abscesses with sinus tract formation and scarring; lesions widely separated
III	Multiple interconnected sinus tracts and abscesses across an entire anatomical region; diffuse or near-diffuse involvement

For dynamic response assessment, the IHS4 score (counting nodules, abscesses, and draining tunnels) provides a quantitative measure of treatment response, complementing the Hurley stage.

Investigations

HS is a clinical diagnosis — no blood test or imaging confirms it. Investigations are used for comorbidity screening and pre-treatment planning:

• FBC, CRP, ESR — baseline inflammation and anaemia of chronic disease
• HbA1c, fasting glucose, and lipid profile — metabolic syndrome screening
• Hormone profile (testosterone, SHBG, LH/FSH) if PCOS is suspected
• TSH
• Vitamin D and ferritin — commonly deficient in chronic inflammatory conditions
• Pre-biologic screen: IGRA or chest X-ray (tuberculosis), HBV surface antigen, anti-HCV, HIV, pregnancy test

Wound swabs have limited value in HS. The condition is not primarily infectious; bacteria identified on culture reflect colonisation rather than the pathogenic driver. Treatment with antibiotics in HS works through anti-inflammatory rather than antimicrobial mechanisms, and culture results should not dictate antibiotic selection.

B. Evidence on treatments — what works and what to avoid

Lifestyle modification

Smoking cessation produces the most significant disease modification of any single intervention. Nicotine and combustion products alter follicular keratinisation, activate pro-inflammatory cytokines including TNF-α and IL-1β, and impair wound healing. Structured cessation support — varenicline, nicotine replacement therapy, bupropion — and referral to Quitline 13 78 48 should be offered at every consultation. The RACGP smoking cessation framework applies.

Weight loss for patients with BMI above 25 is associated with proportional improvement in disease activity. A sustained 15% body weight reduction has been shown in cohort studies to produce clinically meaningful response. The NPS MedicineWise weight management guidance supports a combined dietary and exercise approach.

Practical measures: loose breathable clothing to reduce friction; chlorhexidine 4% or benzoyl peroxide wash for affected areas; avoiding tight synthetic garments; managing occupational heat and friction exposure.

Topical therapy

• Topical clindamycin 1% solution, applied twice daily — first-line topical for Hurley Stage I; modest RCT evidence; General Schedule PBS
• Resorcinol 15% cream (compounded) — some evidence for acute inflammatory nodule management
• Antibacterial washes (chlorhexidine 4%, benzoyl peroxide) — adjunctive; reduce skin surface bacterial load

Oral antibiotics

Per eTG complete:

• Doxycycline 100 mg twice daily × 12 weeks — anti-inflammatory; first-line systemic for Hurley I-II
• Clindamycin 300 mg + rifampicin 300 mg, both twice daily × 10–12 weeks — well-evidenced for Hurley II (European S1 Guideline, Zouboulis et al.); note rifampicin’s significant CYP450 induction — interacts with oral contraceptives, warfarin, HIV antiretrovirals, and many other medications; counsel patients explicitly
• Dapsone 50–200 mg/day — alternative; G6PD screening required before initiation
• Ertapenem 1 g IV daily × 6 weeks — rescue option for refractory severe disease; specialist setting only; bridge to surgery or biologic initiation

Intralesional triamcinolone

Intralesional triamcinolone acetonide (10–40 mg/mL) for individual tender nodules is an effective, office-based procedure that GPs with appropriate training can perform. It provides rapid reduction in pain and lesion size within days. This is not a disease-modifying approach and does not prevent recurrence.

Hormonal therapy for women

• Spironolactone 50–200 mg/day — anti-androgen; useful for women with cyclical premenstrual flares; off-label; monitor potassium and blood pressure
• Combined oral contraceptive with cyproterone component (Diane-35) — anti-androgen; off-label for HS
• Metformin — particularly when PCOS and metabolic syndrome co-exist; modest direct HS benefit

C. Biologic therapy — PBS access in Australia

Adalimumab (Humira) — anti-TNF-α, first-line biologic

The PIONEER 1 and PIONEER 2 trials (Kimball et al., NEJM 2016) were pivotal phase III randomised controlled trials establishing adalimumab as the first biologic with a regulatory indication for HS. Weekly subcutaneous injection of 40 mg (higher frequency than rheumatoid arthritis dosing) achieved the primary endpoint of HiSCR (≥50% reduction in abscess and nodule count) in 42–59% of participants versus 26–27% for placebo.

In Australia, adalimumab is available via PBS Authority (Telephone) for moderate-to-severe HS (Hurley Stage II/III) following failure of conventional therapy. The prescribing authority lies with a dermatologist. Pre-treatment screening — tuberculosis, hepatitis B and C, HIV, pregnancy — must be documented.

Secukinumab (Cosentyx) — anti-IL-17A, second-line biologic

The SUNNY 1 and SUNNY 2 trials (Lancet 2023) established secukinumab’s efficacy in moderate-to-severe HS. PBS Authority for HS was listed in Australia from 2024/2025, making this the first alternative to adalimumab available under the PBS. Dosing is 300 mg subcutaneously every two or four weeks.

Emerging agents

Bimekizumab (anti-IL-17A/F dual blockade, Bimzelx) — TGA approved; PBS pathway is under review. Infliximab, ustekinumab, and brodalumab are available through specialist pathways for selected refractory cases.

All biologic initiation requires dermatology referral. NICE TA716 on adalimumab for HS is referenced by the Australasian College of Dermatologists for evidence grading.

Surgery

Surgery complements medical therapy and is appropriate at any Hurley stage:

• Incision and drainage — acute abscess management; provides relief but does not prevent recurrence; appropriate when fluctuant
• Deroofing — laying open of chronic sinus tracts; tissue-preserving; office-based under local anaesthesia (dermatologist or surgical); high success rate for Hurley II sinus tracts
• Wide local excision with healing by secondary intention, split-skin grafting, or local flap reconstruction — definitive for severe localised Hurley III disease; plastic surgery referral required
• Laser hair removal (Nd:YAG, alexandrite) — adjunctive; reduces follicular occlusion triggers

D. Australian operations

MBS items

Standard GP consultations are billed under items 23, 36, or 44 according to duration and complexity. The GPCCMP (items 965/967) supports structured management of HS as a chronic condition with referral to allied health under the care plan. Mental Health Care Plan preparation (item 2715) and review (item 2717) address the high psychological burden. Procedural items include:

• Item 30219 — incision and drainage of abscess
• Item 18266 — intralesional injection (triamcinolone)
• Items 30068/30069 — wide local excision of soft tissue (surgical/plastic surgery)
• Item 715 — ATSI Health Assessment includes comorbidity screening applicable to HS
• Item 707 — 75+ Annual Health Assessment (comorbidity review)

PBS prescribing

Oral antibiotics (doxycycline, clindamycin), metformin, spironolactone, topical clindamycin, triamcinolone, and chlorhexidine-based washes are General Schedule items. Rifampicin requires documentation of indication (authority for tuberculosis or staphylococcal infection; off-label for HS). Adalimumab (Humira) — Authority Required (Telephone) for moderate-severe HS via dermatologist. Secukinumab (Cosentyx) — Authority Required for HS, PBS-listed 2024/2025. PBS item details: pbs.gov.au.

Referral pathways

• Dermatologist — Hurley II-III, biologic initiation, diagnostic uncertainty, refractory disease after two antibiotic courses
• Plastic surgeon — wide local excision and reconstruction for Hurley III localised disease
• Endocrinologist — hormonal management, PCOS
• Psychologist or psychiatrist — depression, anxiety, suicidal ideation, trauma
• Multidisciplinary HS clinics — available at Royal Prince Alfred Hospital (Sydney) and Royal Melbourne Hospital

Patient resources

• HS Foundation Australia — peer support, advocacy, practical information for patients
• DermNet NZ — Hidradenitis suppurativa — well-regarded patient resource
• HealthDirect — Australian-government consumer health information

E. Special populations

Pregnancy. Many women with HS report improvement during pregnancy; the hormonal environment may reduce follicular occlusion. Topical clindamycin and cefalexin are generally considered safe. Rifampicin, retinoids, and biologic agents require specialist review and individualised risk assessment; most biologics are not recommended in the first trimester without specialist oversight.

Children and adolescents. HS presenting in puberty warrants paediatric dermatology referral. Metabolic and endocrine evaluation is appropriate; early-onset puberty may need investigation.

Patients with inflammatory bowel disease. HS and Crohn’s disease share IL-17 and TNF-α pathways and frequently co-occur. Perianal HS can be confused with Crohn’s perianal fistulae — both can coexist. Adalimumab has PBS indications for both Crohn’s and HS, which may be clinically advantageous for patients with both conditions.

Aboriginal and Torres Strait Islander patients. Metabolic comorbidity including type 2 diabetes and obesity is more prevalent in ATSI communities. The ATSI Health Assessment (MBS item 715) provides a structured opportunity for holistic comorbidity screening. Access to specialist surgical services may require assisted travel.

When to escalate

Refer to a dermatologist when:

• Hurley Stage II or III disease is present
• Two courses of appropriate oral antibiotics (12 weeks each) have not produced adequate response
• Biologic therapy is being considered
• Diagnosis is uncertain

Refer to plastic surgery when:

• Wide local excision and reconstruction is required for Hurley III localised disease

Emergency or urgent referral when:

• Sepsis suspected from an HS-related infection
• Squamous cell carcinoma is suspected in a non-healing, atypical, or long-standing Hurley III lesion — biopsy is mandatory
• Active suicidal ideation — Lifeline 13 11 14, Beyond Blue 1300 22 4636, 13YARN 13 92 76 (First Nations)

What this article is and is not

This article is general health information based on the Australasian College of Dermatologists, eTG complete, NPS MedicineWise, PBS Australia, and the PIONEER (NEJM 2016) and SUNNY (Lancet 2023) trials. It is not personal medical advice and does not create a doctor–patient relationship. Individual treatment decisions are made with your own general practitioner and treating specialists.

For consumer information: HS Foundation Australia, DermNet NZ, HealthDirect.

For mental health crisis: Lifeline 13 11 14, Beyond Blue 1300 22 4636, 13YARN 13 92 76 (First Nations).

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Sources cited

1. Australasian College of Dermatologists — HS Position Statement
2. eTG complete — Hidradenitis suppurativa
3. RACGP
4. NPS MedicineWise
5. PBS Australia — Adalimumab and Secukinumab for HS
6. HS Foundation Australia
7. Kimball AB et al. — PIONEER 1 and 2 trials, adalimumab for HS (NEJM 2016)
8. Zouboulis CC et al. — European S1 HS Guidelines (JEADV 2015 + 2024 update)
9. SUNNY trials — Secukinumab for HS (Lancet 2023)
10. NICE TA716 — Adalimumab for moderate-to-severe HS
11. DermNet NZ — Hidradenitis suppurativa
12. HealthDirect