Hidradenitis suppurativa

Also called HS, Acne inversa

Painful recurring lumps in the armpits, groin and under the breasts. Average time to diagnosis is around seven years, usually spent being treated for boils.

What it is

A chronic inflammatory skin condition causing painful lumps, abscesses and, over time, tunnels under the skin and scarring, in areas where skin rubs: armpits, groin, buttocks, and under the breasts.

It is far more common than most people think, affecting around 1 per cent of the population, and it is severely under-diagnosed. The average delay to diagnosis is around seven years, during which people are typically told they have recurrent boils and given repeated antibiotics and incision and drainage.

The distinguishing feature is recurrence in the same characteristic sites. Two or more episodes in six months in those areas is enough to make the diagnosis clinically; no test is needed.

It is not caused by poor hygiene, and it is not contagious. Both beliefs are widespread and both cause enormous shame. It is associated with smoking and obesity, with inflammatory bowel disease, polycystic ovary syndrome and metabolic syndrome, and it has a strong genetic component.

Treatment has improved substantially: specific antibiotic regimens, hormonal treatment, and biologic drugs for moderate to severe disease. Early dermatology referral changes the course, and repeated courses of flucloxacillin do not.

Signs you might notice

Painful, deep, firm lumps in the armpits, groin, inner thighs, buttocks or under the breasts.

Lumps that come back in the same places, often around the same time in the menstrual cycle.

Abscesses that burst and discharge pus with a strong smell.

Tunnels under the skin joining lumps, and rope-like scarring.

Blackheads appearing in pairs in the affected areas.

Severe pain, often disproportionate to how it looks, and difficulty walking, sitting or lifting the arms.

See a GP and ask for dermatology referral for: two or more episodes in six months in these sites; any tunnelling or scarring; or lesions not settling with a first course of treatment.

Urgent: spreading redness with fever, which may be cellulitis or sepsis.

How it can affect day-to-day life

The pain and the smell are the two things people most want addressed and least often raise. Both are treatable and both drive isolation.

It affects work, intimacy, exercise and clothing, and rates of depression and suicidal thoughts are high. Asking about mood is part of managing it.

Dressings and wound care are a daily reality; a district nurse or practice nurse can help and people often do not know to ask.

Friction, heat and tight clothing provoke flares; loose cotton clothing, absorbent dressings and antiperspirant alternatives help.

Stopping smoking is one of the few things that clearly alters the course, and it is worth framing that way rather than as general advice.

Surgery has a role in severe disease, from deroofing tunnels to wider excision, and is usually done far too late.

Supporting someone well

Name it. If lumps recur in these sites, say hidradenitis suppurativa and ask for dermatology referral rather than accepting recurrent boils.

Do not accept repeated short antibiotic courses as the whole plan; the specific regimens used in HS are different and longer.

Ask about biologic treatment for moderate to severe disease.

Treat the pain properly, including neuropathic pain medication where needed.

Ask for wound care support and appropriate dressings.

Stop smoking; this is the single most effective self-directed change.

Wear loose cotton, reduce friction, and keep the areas cool and dry.

Ask about mood directly and get it treated.

Ask about screening for diabetes and cardiovascular risk, which are raised in HS.

Where to get help

A GP practice, asking specifically for dermatology referral.

A dermatologist, ideally a specialist HS clinic.

Same-day for spreading redness with fever.

Hidradenitis Suppurativa Trust are the UK charity and run peer support.

British Association of Dermatologists publish a patient leaflet.