Hidradenitis suppurativa (HS)

Hidradenitis suppurativa (HS) is a painful, long-term skin condition that causes abscesses and scarring on the skin.

The exact cause of hidradenitis suppurativa is unknown, but it occurs near hair follicles where there are sweat glands, usually around the groin, buttocks, breasts and armpits.

For reasons that are unclear, more women than men have the condition. It's thought to affect about 1% of the population.

Symptoms

The symptoms of hidradenitis suppurativa range from mild to severe.

It causes a mixture of red boil-like lumps, blackheads, cysts, scarring and channels in the skin that leak pus.

The condition tends to start with a firm pea-sized lesion that develops in one place. This will either disappear or rupture and ooze pus after a few hours or days.

New lumps will then often develop in an area nearby. If these aren't controlled with medication, larger lumps may develop and spread. Narrow channels called sinus tracts also form under the skin that break out on the surface and leak pus.

Hidradenitis suppurativa is very painful. The lumps develop on the skin in the following areas:

• around the groin and genitals
• in the armpits
• on the buttocks and around the anus (back passage)
• below the breasts

The abscesses may also spread to the nape of the neck, waistband and inner thighs. Other isolated areas that have been known to be affected include the front or back of the legs, the sides, the back area and even the face.

Some of the lumps may become infected with bacteria, causing a secondary infection that will need to be treated with antibiotics (see below).

Many people with hidradenitis suppurativa also develop a pilonidal sinus, which is a small hole or "tunnel" in the skin.

What causes hidradenitis suppurativa?

The exact cause of hidradenitis suppurativa is unclear, but the lumps develop as a result of blocked hair follicles.

Smoking and obesity are both strongly associated with hidradenitis suppurativa, and if you're obese and/or smoke it's likely to make your symptoms worse.

Hidradenitis suppurativa usually starts around puberty, but it can occur at any age. It's less common before puberty and after the menopause, which may suggest that the sex hormones play a part. Many people with the condition also have acne and hirsutism (excessive hair growth).

In rare cases, hidradenitis suppurativa may be linked to Crohn's disease, particularly if it develops around the groin area and the skin near the anus. Crohn's disease is a long-term condition that causes the lining of the digestive system to become inflamed.

Hidradenitis suppurativa runs in families in about a third of all cases. It's not infectious and isn't linked to poor hygiene.

Diagnosing hidradenitis suppurativa

There's no definitive test to help diagnose hidradenitis suppurativa.

Your GP will examine the affected areas of skin, and they may take a swab of an infected area. This can be helpful in making a diagnosis because the condition isn't usually associated with the presence of bacteria that cause skin infections.

Hidradenitis suppurativa could potentially be mistaken for acne or folliculitis (inflammation of the hair follicles).

Treating hidradenitis suppurativa

Hidradenitis suppurativa is a lifelong, recurring condition that requires constant management and is often difficult to manage.

It's important to try to recognise and diagnose the condition in its early stages and prevent it getting worse.

Treatment for hidradenitis suppurativa will be tailored to the individual. In the early stages, it may be controlled with medication. Surgery may be required in severe or persistent cases. The treatments are outlined below.

Antibiotics

If you have lumps that are particularly painful, inflamed and oozing pus, you may be prescribed a one or two week course of antibiotic tablets, as you may have an infection. However, in hidradenitis suppurativa, a secondary bacterial infection isn't that common, so it's best if a swab of the affected area is taken.

If bacterial infection isn't present, low-dose antibiotics (usually tetracycline) may be used as a suppressive treatment (to prevent inflammation). This longer course of antibiotics will last at least three months, with the aim being to reduce the number of lumps that develop.

Topical antibiotics, such as clindamycin 1% used daily on affected areas can also sometimes help. Oral antibiotics (tablets, capsules or a liquid that you drink) include erythromycin, tetracycline, lymecycline and doxycycline, alongside a number of other options.

In severe cases of hidradenitis suppurativa, a combination of clindamycin and rifampicin can be effective, but these antibiotics are usually prescribed by dermatologists rather than GPs.

Antiseptics

Antiseptic washes, such as 4% chlorhexidine, applied daily to affected areas are often prescribed alongside other treatments.

Retinoids

Retinoids, such as isotretinoin and acitretin, are vitamin-A based medications. They're not as effective for treating hidradenitis suppurativa as they are for treating acne, but they may help some people.

Retinoids are always prescribed by dermatologists. They must be used with caution and can't be taken during pregnancy.

Contraceptives

Women whose hidradenitis suppurativa flares up before their period may benefit from taking the combined contraceptive pill.

Immunosuppressive treatments (Infliximab and adalimumab)

In very severe cases of hidradenitis suppurativa, treatments that suppress the immune system, such as adalimumab (a biological therapy) can be useful.

However, there are risks associated with suppressing the immune system, so they're usually only prescribed by a dermatologist if other treatments don't work.

Infliximab and adalimumab are immunosuppressive treatments that are given by injection at regular intervals either at home or in hospital.

Corticosteroids

Rarely, you may be prescribed a corticosteroid, such as prednisolone, to reduce severely inflamed skin. Corticosteroids can be taken as tablets, or you may have an injection directly into affected skin.

Possible side effects of corticosteroids include weight gain, poor sleep and mood swings.

Read more about the side effects of corticosteroids.

Surgery

Surgery may be considered in cases where hidradenitis suppurativa can't be controlled with medication.

Lifestyle advice

If you have hidradenitis suppurativa you should:

• lose any excess weight
• stop smoking, if you smoke
• use an antiseptic skin wash or antiseptic soap – this may be prescribed alongside other treatment (see above)
• hold a warm flannel on the lumps to encourage the pus to drain
• wear loose-fitting clothes
• avoid shaving affected skin and avoid wearing perfume or perfumed deodorants in the affected areas

Outlook

Although hidradenitis suppurativa can persist for many years, if it's diagnosed early the symptoms can be improved with treatment.

However, the condition can have a significant impact on a person's everyday life. Having to regularly change dressings and constantly live with the pain, discomfort and embarrassment of the symptoms can affect your quality of life and lead to depression.

Speak to your GP if you're having problems coping. Charities, such as The Hidradenitis Suppurativa Trust, can also provide help support.