What Cause Hidradenitis Suppurativa?

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition that causes painful lumps, nodules, and abscesses to form where skin rubs together. It most often affects the armpits, groin, buttocks, and under the breasts. The condition is not caused by poor hygiene, and it is not an infection you can catch from someone else. HS develops when hair follicles become blocked and inflamed, leading to a buildup of pus and scar tissue beneath the skin. Genetics, hormones, and the immune system all play a major role in why some people develop HS and others do not.

What Causes Hidradenitis Suppurativa at the Cellular Level?

HS begins inside the hair follicle, not in the sweat glands as was once believed. In people with HS, the follicle becomes blocked by a plug of keratin and skin cells. When this plug traps bacteria and oil beneath the skin, the follicle ruptures.

The rupture triggers an aggressive immune response. White blood cells flood the area, causing inflammation, swelling, and pain. The body tries to heal the damage by forming scar tissue. Over time, repeated cycles of blockage, rupture, and healing create tunnels under the skin called sinus tracts. These tracts can drain fluid and make the condition harder to treat.

This process explains why HS is classified as an inflammatory disease rather than a simple infection. Bacteria are present in the lesions, but they are not the root cause. The immune system is overreacting to a normal process of hair follicle turnover.

Is Hidradenitis Suppurativa Genetic?

Genetics play a significant role in HS. Research consistently shows that up to 40 percent of people with HS have a close family member who also has the condition. If a parent has HS, a child has a higher chance of developing it, though the inheritance pattern is not simple.

Several gene mutations have been identified that affect how skin cells produce proteins involved in inflammation. One of the most studied is the gamma-secretase gene complex. Mutations in these genes disrupt normal hair follicle function and make the skin more vulnerable to blockage.

Having the genetic predisposition does not guarantee you will develop HS. Many people carry the risk genes but never show symptoms. Environmental and lifestyle factors often determine whether the condition becomes active.

What Role Do Hormones Play in HS?

Hormones clearly influence HS, though the exact mechanism is still being studied. The condition rarely appears before puberty, which points to sex hormones as a trigger. Many women report that their HS flares worsen right before or during their menstrual period.

Androgens, the group of hormones that includes testosterone, are thought to play a role. These hormones increase sebum production and can make hair follicles more prone to blockage. However, most people with HS have normal hormone levels on blood tests. The issue may be that their skin is more sensitive to normal hormone activity.

Pregnancy affects HS differently for different women. Some improve during pregnancy, while others flare. Menopause often brings improvement, likely because hormone levels drop. The evidence is not strong enough to say that hormone therapy reliably treats HS, but the hormonal connection is well established.

How Does Smoking and Obesity Affect HS?

Smoking is one of the strongest modifiable risk factors for HS. Studies have found that people who smoke are significantly more likely to develop HS than non-smokers. The link is so strong that some researchers consider smoking a trigger for the disease rather than just a risk factor.

Nicotine affects the skin in several ways. It narrows blood vessels, reduces oxygen delivery to tissues, and alters the immune response. These changes make hair follicles more likely to block and rupture. People with HS who quit smoking often report fewer and less severe flares, though the disease does not disappear entirely.

Obesity is also strongly associated with HS. Excess weight creates more skin folds, which increases friction and moisture in areas where HS develops. Adipose tissue, or body fat, produces inflammatory molecules that can worsen the immune response. Weight loss has been shown to improve HS symptoms in some people, especially when the weight is lost in areas where flares occur.

Neither smoking nor obesity causes HS on its own. Many people who smoke and carry excess weight never develop the condition. But both factors significantly increase the risk and tend to make the disease more severe.

What Are the Other Risk Factors for HS?

Several other factors increase the likelihood of developing HS. The condition is more common in women than men by a ratio of about three to one. It is also more common in people of African descent and in those with a family history of the disease.

Metabolic conditions are linked to HS. People with diabetes, metabolic syndrome, and insulin resistance have higher rates of HS. The inflammation that drives HS is also present in these metabolic conditions, which may explain the overlap.

Certain medications can trigger or worsen HS. Lithium, which is used for bipolar disorder, has been associated with HS flares. Some biologic medications used for other autoimmune diseases have also been reported to cause HS-like lesions, though this is uncommon.

Friction and pressure on the skin do not cause HS, but they can provoke flares in someone who already has the condition. Tight clothing, heavy sweating, and mechanical irritation from skin rubbing together are common triggers for existing lesions.

What Does Not Cause Hidradenitis Suppurativa?

HS is not caused by poor hygiene. Washing more frequently or using antibacterial soaps will not prevent or cure the condition. The blockage happens deep inside the hair follicle, where surface washing cannot reach.

HS is not a sexually transmitted infection. It appears in the groin and genital area, which leads some people to worry it is contagious. It is not. You cannot pass HS to a partner through any kind of contact.

HS is not caused by shaving or waxing. These activities can irritate the skin and may trigger a flare if you already have HS, but they do not cause the disease to develop in the first place. The underlying problem is the follicle’s tendency to block, not the method of hair removal.

HS is not an allergy. Food allergies and sensitivities do not cause HS, although some people report that certain foods like dairy or high-glycemic carbohydrates seem to worsen their flares. The evidence for dietary triggers is limited and varies widely between individuals.

Can Hidradenitis Suppurativa Be Prevented?

There is no known way to completely prevent HS, especially if you have a strong genetic predisposition. However, you can reduce your risk and possibly delay the onset of the disease by addressing modifiable factors.

Not smoking is the most important preventive step. If you smoke, quitting reduces your risk. Maintaining a healthy weight also lowers your risk, particularly if you avoid excess weight in the armpit, groin, and thigh areas.

For people who already have HS, prevention focuses on reducing flares rather than stopping the disease from starting. Gentle skin care, loose clothing, and avoiding skin trauma can help. Some dermatologists recommend using antibacterial washes containing chlorhexidine or benzoyl peroxide to reduce bacteria on the skin surface, though this does not treat the underlying inflammation.

When Should You See a Doctor?

See a doctor if you have painful lumps under the skin that do not go away within a few weeks, especially if they recur in the same areas. HS is often misdiagnosed as boils, ingrown hairs, or simple infections. A dermatologist is the specialist most qualified to diagnose and treat HS.

Early diagnosis matters. Treatment is more effective when started before extensive scarring and sinus tracts develop. A doctor can distinguish HS from other conditions that look similar, such as infected cysts, folliculitis, or inflammatory bowel disease-related skin lesions.

Treatment options include topical medications, oral antibiotics, biologic drugs that target specific inflammatory pathways, and in severe cases, surgery. The right treatment depends on the severity of your disease and how it has responded to previous therapies.