Hidradenitis Suppurativa
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Direct answer
Hidradenitis suppurativa is a chronic, recurrent inflammatory disease of apocrine-rich skin that produces painful deep nodules, abscesses, sinus tracts and scarring in the axillae, groin and inframammary folds. Severity is graded by Hurley staging, from single abscesses without tracts to diffuse, interconnected sinus disease. Treatment escalates from topical clindamycin and lifestyle measures to oral antibiotics, TNF-alpha inhibitors such as adalimumab, and surgery for established disease.
What you must remember
- Distribution: apocrine-rich sites, chiefly the axillae, inguinal and perianal skin, inframammary folds, buttocks and genitals.
- Lesions: painful, deep-seated nodules and abscesses that recur, drain and leave sinus tracts and scarring.
- Onset: typically after puberty, with activity most often in young adults.
- Hurley stage I: single or few abscesses without sinus tracts or scarring.
- Hurley stage II: recurrent abscesses with tracts and scarring, separated by areas of normal skin.
- Hurley stage III: diffuse involvement with multiple interconnected tracts and abscesses across the whole area.
- Modifiable risks: smoking and obesity are the strongest modifiable factors, and the disease is associated with metabolic syndrome.
- Biologics: adalimumab, a TNF-alpha inhibitor, is licensed for moderate to severe disease, and secukinumab, an IL-17A inhibitor, is also licensed.
Staging and escalating treatment
A 27-year-old woman has painful axillary nodules that have recurred for two years, with two draining sinuses and smoking as a daily habit. Her management follows the Hurley stage and the disease burden, and each step is applied in sequence.
- Recognise the pattern: Painful, recurrent nodules in apocrine sites, with sinuses and scarring, mark hidradenitis rather than simple boils. Incision of one abscess alone will not prevent the next.
- Stage the disease: Assign Hurley stage I, II or III based on tracts, scarring and the extent of interconnected disease. The stage determines whether medical or surgical options dominate.
- Treat early disease topically: Topical clindamycin is used for mild stage I disease, alongside antiseptic washes and weight and smoking advice. Pain control and drainage are given for acute abscesses.
- Add oral antibiotics: Tetracycline-class antibiotics or a combination such as clindamycin with rifampicin is used for moderate stage II disease, usually for a limited course. Antibiotics control flares rather than curing the disease.
- Introduce a biologic: Adalimumab is considered for moderate to severe disease that is not controlled by antibiotics, after screening for tuberculosis as required for biologics. Secukinumab is an alternative in licensed settings.
- Consider surgery: Deroofing or wide excision is used for established stage III disease with tracts, after the inflammation has been controlled. Smoking cessation and weight management support every stage.
Where the exam tries to catch you
Hidradenitis questions test staging, the site-based distinction from other disorders and the limits of antibiotic therapy.
- Trap: treating recurrent axillary abscesses as furuncles with simple incision and no further plan. Correct: hidradenitis is chronic, so staging and long-term therapy are required, and incision alone leads to recurrence.
- Trap: using long-term antibiotics as definitive therapy for severe disease. Correct: antibiotics are adjunctive, and biologics or surgery are needed for moderate to severe and tract-forming disease.
- Trap: confusing hidradenitis with acne conglobata because both form sinuses. Correct: hidradenitis affects apocrine sites such as the axillae and groin, whereas conglobata favours the face, back and chest.
- Trap: regarding hidradenitis as purely infective. Correct: it is an inflammatory disorder with follicular occlusion and immune dysregulation, which is why immunological therapy is central in severe cases.
Frequently asked questions
What are the Hurley stages of hidradenitis suppurativa?
Hurley stage I is single or few abscesses without sinus tracts or scarring, stage II is recurrent abscesses with tracts and scarring separated by normal skin, and stage III is diffuse, interconnected tracts and abscesses across the affected area. The stage guides whether medical or surgical treatment is chosen.
Which biologic is used for moderate to severe hidradenitis suppurativa?
Adalimumab, a TNF-alpha inhibitor, is used for moderate to severe hidradenitis suppurativa that is not controlled by antibiotics. It is started after screening, including for tuberculosis, and secukinumab, an IL-17A inhibitor, is also licensed for this indication.
Which body sites are typically affected by hidradenitis suppurativa?
Hidradenitis suppurativa typically affects apocrine-rich sites, chiefly the axillae, inguinal and perianal skin, inframammary folds, buttocks and genitals. The face is spared, which helps distinguish it from acne conglobata.
Why are smoking and obesity important in hidradenitis suppurativa?
Smoking and obesity are the strongest modifiable risk factors for hidradenitis suppurativa and are associated with more severe disease. Addressing them is part of every treatment stage, alongside medical and surgical therapy.