Hidradenitis suppurativa, often shortened to HS, is a painful and potentially scarring skin disease thought to affect around one in 100 people in Britain — yet it remains largely unknown to the wider public.
The long-term inflammatory condition triggers sore, boil-like nodules that develop deep beneath the skin, most commonly in places where skin rubs together, including the underarms and groin.
HS is linked to blocked hair follicles, and in its early stages flare-ups may be mistaken for ingrown hairs. Without effective treatment, however, the disease can progress to open, draining wounds that may eventually require surgery to remove damaged skin.
For years, people living with hidradenitis suppurativa have typically been offered antibiotics, antiseptic washes and medication to manage pain. But in more severe cases, these approaches often fail to stop repeated outbreaks or fully control the disease.
Now dermatology experts say emerging research points to a new class of medicines that may tackle HS closer to its source by calming the inflammation that fuels it.
Known as JAK inhibitors, the drugs are already prescribed for several inflammatory illnesses, including rheumatoid arthritis and eczema. Scientists are increasingly exploring their potential as a treatment for hidradenitis suppurativa because they work by interrupting inflammatory messages inside cells.
Although JAK inhibitors cannot undo the extensive skin damage seen in advanced HS, they may prove to be “a gamechanger” for people with milder or earlier-stage disease, according to Dr Abirami Pararajasingam, consultant dermatologist and spokesperson for the British Skin Foundation.
Dr Pararajasingam says doctors in the US have been more “proactive” in offering these medicines to patients, partly because there are fewer barriers to earlier medical intervention.
Laurelle-Maria Sterling, 32, has lived with HS since her teens – a drug called adalimumab greatly reduced the level of inflammation for her
A chronic inflammatory disease, HS causes painful, boil-like lumps to form deep under the skin in areas such as the armpits and groin (picture posed by model without HS)
But she adds: ‘In the UK, there are issues with pricing that mean patients can’t access them. Not only is HS painful and, for many, embarrassing, chronic inflammation is also a risk factor for other long-term health issues – from heart disease to stroke. We need to be intervening earlier.’
Once thought to be rare, more than 700,000 Britons are now estimated to have HS. One of the most famous sufferers was political theorist Karl Marx.
Caused by an overactive immune system which triggers an abnormal inflammatory response when hair follicles become blocked and infected, it can vary widely in severity.
For some, flare-ups resemble small blackheads, boils or under-the-skin lumps that go on their own. For others, lesions become open wounds that take years to heal and cause extensive scarring. Women are more likely to be affected than men, with most experiencing symptoms in their early to late teens.
As the condition often appears to mimic other common ailments and lacks a single definitive lab test, HS can take up to ten years to diagnose in the UK.
As a result, says Dr Beibei Du-Harpur, clinical lecturer in dermatology at King’s College London, many patients live for years without understanding what is going on.
‘If HS is diagnosed and treated early, much of the worst damage can be avoided,’ she says. ‘[But] people are just sitting at home coping as that damage is occurring because they don’t understand what’s happening. This lack of awareness is also a huge issue among clinicians.’
Experts still aren’t sure exactly what causes the condition, but it’s estimated that one in three cases is genetic. Other factors are being overweight and smoking.
Nicotine and other chemicals in tobacco smoke bind to receptors in skin cells, encouraging abnormal skin thickening which blocks hair follicles. Being overweight can see pro-inflammatory chemicals released by excess fat tissue, creating a low-grade inflammation that can trigger or worsen HS.
One of the most famous sufferers of HS was Karl Marx, who lived in the 19th century
Many patients live for years without understanding what is going on, says Dr Beibei Du-Harpur, clinical lecturer in dermatology at King’s College London
Extra body weight can also create deeper skin folds, under which HS eruptions can occur. But not all sufferers are smokers or overweight. ‘Some people are simply more prone to HS because of their hair follicle and oil gland structure,’ says Dr Du-Harpur.
Early cases of HS are usually treated with courses of antibiotics and prescription creams or gels. But research has led to huge advancements now beginning to trickle down to patients in the UK.
Called biologics, this new range of drugs target and block specific immune system proteins that drive painful inflammation and tissue damage, reducing flare-ups and preventing future outbreaks.
For many, the drugs have already been life-changing. Laurelle-Maria Sterling, 32, has lived with HS since her teens. Diagnosed at 20, when she was regularly in and out of hospital, she was prescribed course after course of antibiotics.
‘None of them got rid of the HS,’ she says. ‘My only option was surgery – great for pain relief, as the pain from healing is better than the pain from the condition – but it didn’t stop flare-ups in other areas.’
Four years ago she was put on a drug called adalimumab, also used to treat rheumatoid arthritis and psoriasis. She says: ‘It calmed down the level of inflammation. I still get occasional flare-ups but they no longer become as severe.’
In the US, adalimumab and JAK inhibitors are already used to treat milder cases of HS. A study published in Nature found JAK inhibitor povorcitinib cut inflammatory nodules and abscesses in HS patients by more than 50 per cent.
The ‘promising’ JAK inhibitor drugs should be rolled out by the NHS for HS patients in the next year or two, says Dr Du-Harpur.
