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[Conditions](https://durgical.com/en/conditions/) · [Dermatology](https://durgical.com/en/conditions/)

# Hidradenitis suppurativa

Hidradenitis suppurativa causes painful lumps, abscesses and draining tunnels in the armpits, groin and skin folds. It is not caused by poor hygiene.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Skin](https://durgical.com/en/anatomy/skin/)

## Why it happens

- [Chronic inflammation: causes, cells and features](https://durgical.com/en/general-pathology/chronic-inflammation-causes-cells-and-features/)
- [Outcomes of acute inflammation: resolution, abscess, scar or chronic inflammation](https://durgical.com/en/general-pathology/outcomes-of-acute-inflammation-resolution-abscess-scar-or-chronic-inflammation/)
- [Hair follicles, sebaceous and sweat glands, nails](https://durgical.com/en/histology/hair-follicles-sebaceous-and-sweat-glands-nails/)

## What it is

A chronic, recurrent inflammatory disease of the hair follicle (follicular occlusion) affecting apocrine gland-bearing skin of the axillae, groin, perineum, buttocks and under the breasts. It causes deep painful nodules, abscesses, sinus tracts (tunnels) and scarring.

## Who gets it

Affects about 1% of people, more often women, starting after puberty, usually in the 20s; more frequent in people with obesity and in smokers. It is underdiagnosed and often mistaken for recurrent boils, with long delays to diagnosis.

## Causes

- Occlusion of the hair follicle with rupture and an inflammatory reaction, not a primary infection
- Immune dysregulation (IL-17, TNF-alpha and IL-1 pathways)
- Genetic predisposition (family history in about a third; gamma-secretase gene mutations in some families)
- Hormonal influence, with flares around menstruation

## Risk factors

- Smoking
- Obesity and metabolic syndrome
- Family history
- Female sex, puberty to middle age
- Friction from tight clothing; polycystic [ovary](https://durgical.com/en/anatomy/ovary/) syndrome and Crohn disease

## Pathophysiology

Follicular hyperkeratosis plugs the hair follicle, which dilates and ruptures, spilling keratin and bacteria into the dermis. This triggers a strong innate and Th17 immune response with neutrophils, forming painful nodules and abscesses. Repeated cycles create epithelialised sinus tracts and dense scar tissue, which keep inflammation going.

## Classification

- Hurley stage I: isolated abscesses without sinus tracts or scarring
- Hurley stage II: recurrent abscesses with sinus tracts and scarring, separated by normal skin
- Hurley stage III: diffuse involvement with interconnected tracts across the whole area

## Symptoms and signs

- Recurrent painful, deep nodules in the armpits, groin, inner thighs, buttocks or under the breasts
- Abscesses that rupture and drain foul-smelling pus or blood
- Sinus tracts (tunnels) that drain chronically
- Double-ended comedones (tombstone blackheads)
- Rope-like scarring and restricted movement
- Major impact on quality of life, sleep, work and mood

## Red flags

- Fever, spreading redness or signs of sepsis
- A non-healing ulcer or growing mass in long-standing buttock or perineal disease (possible squamous cell carcinoma)
- Severe pain, depression or suicidal thoughts
- Diarrhoea, abdominal pain or perianal fistulas suggesting Crohn disease

## Diagnosis

**Clinical**
Clinical: typical lesions (deep nodules, abscesses, tunnels, scars), typical sites, and recurrence (at least twice in 6 months). Stage with Hurley.

**Tests**
No specific test. Culture only if secondary infection is suspected; screening for diabetes, lipids and other comorbidities; biopsy for atypical or non-healing lesions.

**Imaging**
[Skin](https://durgical.com/en/anatomy/skin/) ultrasound shows the extent of tunnels and fluid collections and helps plan surgery; MRI for complex perineal disease.

## Differential diagnosis

- Furuncles and carbuncles (Staphylococcus aureus)
- Infected epidermoid cyst
- Pilonidal disease
- Crohn disease with perianal or cutaneous fistulas
- Lymphogranuloma venereum, scrofuloderma (cutaneous tuberculosis), actinomycosis

## Goal of treatment

Reduce flares, pain and drainage, stop progression to tunnels and scars, treat comorbidities and support quality of life; treatment escalates with Hurley stage.

## Treatment

**Lifestyle**
Stopping smoking, weight loss, loose clothing, gentle cleansing and wound care; pain control and psychological support.

**Medical**
Mild disease: topical clindamycin and antiseptic washes; intralesional corticosteroid for acute painful nodules.

**Medical**
Moderate disease: oral tetracyclines, or clindamycin with rifampicin; hormonal therapy or metformin in selected women.

**Medical**
Moderate to severe disease: biologic agents (TNF-alpha inhibitors such as adalimumab, IL-17 inhibitors such as secukinumab).

**Surgical**
Deroofing of tunnels, local excision, or wide excision of the affected area in Hurley III; simple incision and drainage gives only short relief.

## Drugs for this condition

- [Adalimumab](https://durgical.com/en/pharmacology/adalimumab/)
- [Secukinumab](https://durgical.com/en/pharmacology/secukinumab/)

## Complications

- Extensive scarring and contractures limiting arm or leg movement
- Chronic pain, depression, anxiety and social isolation
- Secondary infection and, rarely, sepsis
- Lymphoedema of the genitals or limbs
- Squamous cell carcinoma in long-standing gluteal or perineal disease
- Anaemia of chronic inflammation; association with spondyloarthritis

## Prognosis

Chronic and relapsing; early diagnosis and treatment can slow progression. Advanced disease usually requires biologics and surgery. Smoking and obesity worsen the course.

## Test yourself

Think of the answer, then tap the question to see it.

## Is hidradenitis suppurativa primarily an infection?

No; it is a chronic inflammatory disease of follicular occlusion, although secondary infection can occur.

## Which two modifiable risk factors are most strongly linked to hidradenitis suppurativa?

Smoking and obesity.

## What staging system is used for hidradenitis suppurativa?

The Hurley staging system (I to III), based on tunnels and scarring.

## Which biologic class is approved for moderate to severe hidradenitis suppurativa?

TNF-alpha inhibitors (adalimumab); IL-17 inhibitors are also used.

## Which cancer can arise in long-standing perineal or gluteal hidradenitis?

Squamous cell carcinoma.

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## Related conditions

- [Obesity](https://durgical.com/en/conditions/obesity/)
- [Metabolic syndrome](https://durgical.com/en/conditions/metabolic-syndrome/)
- [Type 2 diabetes mellitus](https://durgical.com/en/conditions/type-2-diabetes-mellitus/)
- [Polycystic ovary syndrome](https://durgical.com/en/conditions/polycystic-ovary-syndrome/)
- [Crohn disease](https://durgical.com/en/conditions/crohn-disease/)
- [Acne vulgaris](https://durgical.com/en/conditions/acne-vulgaris/)
- [Pilonidal disease](https://durgical.com/en/conditions/pilonidal-disease/)
- [Cutaneous squamous cell carcinoma](https://durgical.com/en/conditions/cutaneous-squamous-cell-carcinoma/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Hidradenitis Suppurativa](https://medlineplus.gov/hidradenitissuppurativa.html) (MedlinePlus, US National Library of Medicine, 2026); [Hidradenitis suppurativa: Overview](https://www.aad.org/public/diseases/a-z/hidradenitis-suppurativa-overview) (American Academy of Dermatology, 2026).

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Source: https://durgical.com/en/conditions/hidradenitis-suppurativa/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/hidradenitis-suppurativa/