5.4 Hidradenitis Suppurativa, Hyperhidrosis & Other Sweat Gland Disorders
Key Takeaways
- Hidradenitis suppurativa is a chronic inflammatory follicular disease with painful nodules, abscesses, and draining tunnels in the axillae, groins, and anogenital region, affecting about 1% of Europeans in many estimates.
- The IHS4 severity score equals the number of nodules plus 2 times abscesses plus 3 times draining tunnels, with 3 or less mild, 4 to 10 moderate, and 11 or more severe.
- Adalimumab, secukinumab, and bimekizumab are approved in the EU for moderate-to-severe hidradenitis suppurativa after inadequate response to conventional systemic therapy.
- Oral clindamycin 300 mg twice daily with rifampicin 300 mg twice daily for about 10 to 12 weeks is a standard European regimen for moderate hidradenitis suppurativa.
- Primary focal hyperhidrosis is bilateral, symmetric, starts before about 25 years of age, and stops during sleep, whereas generalised or nocturnal sweating needs a search for secondary causes.
5.4 Hidradenitis Suppurativa, Hyperhidrosis & Other Sweat Gland Disorders
Hidradenitis Suppurativa (HS)
HS (acne inversa) is a chronic, inflammatory, recurrent, and debilitating disease of the hair follicle. It usually starts after puberty and causes painful deep nodules, abscesses, and draining tunnels (sinus tracts) in skin folds. It is often diagnosed late and has a heavy impact on quality of life, work, and mood.
Epidemiology and Pathogenesis
- Prevalence: estimates vary widely; about 1% is commonly quoted for Europe. In Europe, women are affected more often than men.
- Risk factors: smoking and obesity are the strongest modifiable factors. There is often a family history.
- Pathogenesis: infundibular hyperkeratosis blocks the follicle, which dilates and ruptures. The contents trigger inflammation involving TNF-alpha, IL-1, and IL-17, followed by tunnel formation and scarring. It is not primarily an infection or a disease of apocrine glands.
- Genetics: some familial cases carry mutations in gamma-secretase genes (NCSTN, PSENEN, PSEN1).
- Associations: Crohn disease, spondyloarthritis, metabolic syndrome, polycystic ovary syndrome, depression, and the follicular occlusion tetrad (HS, acne conglobata, dissecting cellulitis of the scalp, and pilonidal sinus). Syndromic forms include PASH (pyoderma gangrenosum, acne, suppurative hidradenitis) and PAPASH (adding pyogenic arthritis).
- Complications: anaemia, secondary amyloidosis, lymphoedema, and squamous cell carcinoma in long-standing gluteal and perineal disease, more often in men.
Diagnosis
Diagnosis is clinical and needs all three:
- Typical lesions: deep painful nodules, abscesses, draining tunnels, bridged scars, and double-ended comedones.
- Typical sites: axillae, groins, inner thighs, perineal and perianal skin, buttocks, and inframammary folds.
- Chronicity and recurrence: for example, at least two flares within 6 months.
Severity Scores
| Tool | Definition |
|---|---|
| Hurley I | Single or multiple abscesses without tunnels or scarring |
| Hurley II | Recurrent abscesses with tunnels and scarring; single or multiple widely separated lesions |
| Hurley III | Diffuse involvement, with multiple interconnected tunnels and abscesses across the whole area |
| IHS4 | (Nodules × 1) + (Abscesses × 2) + (Draining tunnels × 3); ≤ 3 mild, 4–10 moderate, ≥ 11 severe |
| HiSCR | Response measure: at least 50% fewer abscesses and inflammatory nodules, with no increase in abscesses or draining tunnels |
European Treatment Approach
| Situation | Options |
|---|---|
| All patients | Stop smoking, lose weight, pain control, dressings, treat depression; screen for comorbidity |
| Mild (Hurley I, few lesions) | Topical clindamycin 1%; intralesional triamcinolone for painful nodules; antiseptic washes |
| Mild-to-moderate, widespread | Oral tetracycline (doxycycline or lymecycline) for about 12 weeks |
| Moderate | Oral clindamycin 300 mg twice daily + rifampicin 300 mg twice daily for about 10–12 weeks |
| Moderate-to-severe, not responding | Biologics: adalimumab (160 mg at week 0, 80 mg at week 2, then 40 mg weekly or 80 mg every other week); secukinumab (IL-17A); bimekizumab (IL-17A and IL-17F) |
| Other options | Acitretin, dapsone, antiandrogens or metformin in women, and intravenous ertapenem for severe flares in specialist centres |
| Surgery (any stage for fixed lesions) | Deroofing of tunnels; wide local excision; CO2 laser excision. Simple incision and drainage relieves pain from an acute abscess but is followed by high recurrence |
Rifampicin is a strong enzyme inducer. It reduces the effect of hormonal contraception and many other drugs, and it colours urine and tears orange. Adalimumab is licensed in the EU for adults and adolescents from 12 years with active moderate-to-severe HS and an inadequate response to conventional systemic therapy. The best results come from combining medical treatment with surgery for established tunnels.
Hyperhidrosis
Primary Focal Hyperhidrosis
Excessive sweating beyond thermoregulatory need, usually of the axillae, palms, soles, or face. Typical features are:
- bilateral and symmetric sweating;
- onset before about 25 years;
- at least one episode a week;
- no sweating during sleep;
- a positive family history;
- impaired daily activities.
Severity is often graded with the Hyperhidrosis Disease Severity Scale (HDSS) from 1 (never noticeable) to 4 (intolerable, always interfering). The Minor starch-iodine test maps the sweating area before botulinum toxin.
Secondary Hyperhidrosis
Generalised, asymmetric, or nocturnal sweating, or onset in later adult life, suggests a secondary cause: fever and infection (tuberculosis, endocarditis), hyperthyroidism, diabetes and hypoglycaemia, phaeochromocytoma, carcinoid, lymphoma and other cancers, menopause, anxiety, neurological disease, and drugs (antidepressants, opioids, cholinergic drugs). Gustatory sweating after parotid surgery is Frey syndrome.
Treatment Ladder for Primary Hyperhidrosis
| Step | Treatment | Notes |
|---|---|---|
| 1 | Topical aluminium chloride hexahydrate (10–30%) at night | Irritation is the main side effect |
| 2 | Topical anticholinergic (glycopyrronium bromide cream for axillae) | Approved in several EU countries for severe primary axillary hyperhidrosis in adults |
| 3 | Tap-water iontophoresis | First choice for palms and soles |
| 4 | Botulinum toxin type A injections | Effect lasts about 4–9 months; for palms, risk of temporary hand weakness |
| 5 | Oral anticholinergics (oxybutynin, glycopyrronium) | Off-label; dry mouth, blurred vision, urinary retention |
| 6 | Microwave thermolysis or local surgery (axillae) | Specialist centres |
| 7 | Endoscopic thoracic sympathectomy | Last resort for palmar disease; compensatory hyperhidrosis elsewhere is common and can be worse |
Other Sweat Gland Disorders
| Disorder | Gland | Features |
|---|---|---|
| Miliaria crystallina | Eccrine (duct blocked in stratum corneum) | Clear 1–2 mm vesicles like water drops after fever or heat, no inflammation |
| Miliaria rubra (prickly heat) | Eccrine (blockage deeper in epidermis) | Itchy red papules in covered areas in hot, humid weather |
| Miliaria profunda | Eccrine (dermal level) | Flesh-coloured papules after repeated miliaria rubra; can cause heat exhaustion |
| Fox-Fordyce disease | Apocrine | Itchy follicular papules in the axillae of young women ("apocrine miliaria") |
| Bromhidrosis | Apocrine (mainly) | Offensive odour from bacterial breakdown of sweat |
| Chromhidrosis | Apocrine | Coloured sweat (lipofuscin) |
| Anhidrosis / hypohidrosis | Eccrine | Hypohidrotic ectodermal dysplasia (usually X-linked EDA), Fabry disease, Ross syndrome, neuropathy, and drugs; risk of heat stroke |
A 30-year-old woman has recurrent painful abscesses in both axillae with multiple interconnected draining tunnels and scarring across the entire axilla on both sides. What is her Hurley stage?
A patient with hidradenitis suppurativa has 4 inflammatory nodules, 2 abscesses, and 1 draining tunnel. What is the IHS4 score and severity?
A 26-year-old woman with moderate hidradenitis suppurativa, taking a combined oral contraceptive, is started on oral clindamycin and rifampicin. What important advice must she receive?
A 58-year-old man reports new drenching generalised sweating over the last 3 months, which wakes him at night, and 6 kg weight loss. What is the most appropriate approach?