Hidradenitis Suppurativa or HS is a common inflammatory skin condition involving the development of painful spots and abscesses mainly in the armpits, groin and underneath the breasts
What is this skin condition?
Hidradenitis Suppurativa or HS is a common inflammatory skin condition involving the development of painful spots and abscesses mainly in the armpits, groin and underneath the breasts. It can occur on the abdomen and thighs particularly in patients who are over weight. Involvement of the buttocks is also sometimes seen, most commonly in male smokers. The skin lesions are often painful and in severe cases can become persistent and leak pus.
Why have I got it?
The precise cause of HS is not known. As with most diseases there are likely to be genetic and environmental causes. The disease is focussed in areas of the body where there are naturally more bacteria. The disease process involves structures in the skin where bacteria can accumulate such as apocrine sweat glands and hair follicles. There are probably 2 things that need to happen to develop HS:-
HS is far more common in people who are overweight or who smoke, with 90% of HS sufferers being either overweight or smokers. If you are overweight your flexural areas (armpits, groin) are less exposed to the air and are warmer leading to a greater chance for bacterial overgrowth. Smoking is thought to lead to blockages in skin structures as the cancer forming chemicals affect the way the skin cells grow. However , most people who are overweight or smoke do not get HS and some normal weight non-smokers get HS.
This can be explained by a 2 hit hypothesis involving (1) bacterial overgrowth and (2) an oversensitive immune system.
For HS to occur you need both things to happen. Some people are born with a tendency to skin structure blockages (there are some links to a gene which makes a protein that helps to keep skin structures open), others are born with an oversensitive skin immunity and some are born with both. If you have both risk factors you will get HS even if you are thin and do not smoke. If you only have the oversensitive skin immunity you will be okay as long as you do not trigger your immune system. However, if you smoke or become overweight and develop blockages of your sweat glands or hair follicles, leading to increased bacterial growth, you will trigger your sensitive skin immunity and go on to get the inflamed spots and abscesses of HS.
We should emphasize that the above explanation remains a hypothesis. The precise cause of HS is likely to be complex. Clinical experience shows us that there are definitely different types of HS and the cause is likely to differ between individuals.
These images show axillary HS at different stages of inflammation. Image 1 shows HS with scarring but minimal inflammation whereas image 2 shows more inflammation with early hypertrophic scar formation.
Comparing the treatment options:
Treatment of HS has 3 main strategies
If you are over-weight you must try and lose weight. If you smoke, you must stop smoking. Successful treatment of HS is hard and you need to do everything you can to reduce the tendency for HS lesions to appear. There are of course thin, non smokers with HS and so it is not guaranteed that correcting these issues will help. However, the association between HS and smoking and excess weight is significant and cannot be ignored.
Washing with an antibacterial product such as hibiscrub may be helpful. This can be purchased from the chemist or from amazon via this link.
Help from your GP
Help from a Dermatologist
Help from a plastic Surgeon
In severe cases of HS the chronic inflammation leads to fixed abscesses which connect to the skin surface by channels called fistulas. Once these become established, bacteria grow within them and the action of the immune system on the bacteria produces pus which is discharged. These structural changes do not respond to medical treatment and sometimes surgery is needed. To be effective large areas of abnormal skin will sometimes need to be removed. This can lead to significant scarring but patients are often very grateful to be relived of the pain and discharge. In larger hospitals severe HS is increasingly managed by teams of Dermatologists and plastic Surgeons working together.
Other sources of information:
The British Association of Dermatologists have an information leaflet.
Dermnet NZ have an information page on their website.