What Are Causes And Risk Factors of Hidradenitis Suppurativa?

Hidradenitis suppurativa, or HS, is a chronic inflammatory skin disease. The pain, appearance, and odor can have serious effects on quality of life.1

The disease begins when clogged hair follicles cause bumps. The process leads to abscess formation, drainage, and inflammation, which can cause tunnels under the skin, and permanent scar formation.2

Research has not proved an exact cause for HS, but most doctors feel it is a combination of genetic and environmental factors.3

Cause vs. risk

Genes may cause part of the process that leads to HS. This means that people who have HS may inherit a genetic mutation (change) that causes the condition from one of their parents. When symptoms begin and the development of HS may require more than one gene and may require other factors to trigger the process.4

Risk factors increase the chances of being diagnosed with HS. For instance, more women than men have HS, which means that being female is a risk factor for HS, but it does not cause HS.5

Risk factors for HS

Family history

Up to 40 percent of people with HS have a family history of the disease.3

The body’s DNA is stored on chromosomes. We have 2 copies of 23 chromosomes, with 1 copy coming from each of our parents. Each chromosome contains many genes. Genes carry the information that determine what features are inherited from your parents. Researchers have found some causes of HS have resulted from mutations (changes) in the NCSTN, PSEN1, or PSENEN gene. A person only needs a mutation in one copy of these different genes to have a higher risk of developing HS.6

Obesity

About 88 percent of people with HS are obese. Obesity increases the severity of HS in several ways:2,3

  • Body fat may produce higher levels of hormones that cause inflammation
  • Obesity increases pressure on hair follicles and on lesions, or sores. Pressure leads to rupture of the follicles
  • Dietary habits make cells more sensitive to androgen (male hormone) and increase plugging of follicles

Smoking

Smoking increases risk of HS and the severity of symptoms. Nicotine in tobacco increases the plugging of follicles. Up to 75 percent of people with HS smoke. Another 10 to 15 percent are former smokers.3,7

Other health conditions

Metabolic syndrome – People with metabolic syndrome have 3 or more of these conditions: high blood pressure, high blood sugar, excess body fat around the waist, and high cholesterol or triglyceride levels. This increases the risk for heart disease, stroke, and type 2 diabetes. People with HS are nearly 4.5 times more likely to have metabolic syndrome than healthy people without HS.2

Thyroid disease – The thyroid gland produces hormones that control metabolism to release energy for the body to function. In a U.S. study of 14 million people, people with HS had higher rates of overproduction and under-production of thyroid hormones than people without HS. Each condition was more common in people with more severe HS than in people with mild HS.8

Joint disease – In diseases such as rheumatoid arthritis, the body's immune system mistakenly attacks organs, tissues, and joints. Inflammation leads to swelling and pain. In one study, about 29 percent of people with HS had pain in muscles and bones.2

Inflammatory skin conditions – Some of the inflammatory skin conditions linked to HS include:9

Pyoderma gangrenosum – inflammatory, noninfectious skin disease causing large, painful skin lesions or ulcers

Psoriasis – itchy, red, scaly white plaques of skin

Vitiligo – depigmented (loss of pigment) macules or patches on the skin

Axial spondyloarthritis (AxSpA) – This inflammatory condition leads to arthritis in the spine and pelvic joints. People with AxSpA have a higher rate of HS than the general population and may have more severe HS disease.9

Inflammatory bowel disease (IBD) – People with IBD are 9 times more likely to develop HS than the general population.2

Polycystic ovary syndrome (POCS) – High levels of androgen in women, irregular menstrual periods, and cysts on the ovaries mark this hormonal disorder. The likelihood of people with HS having POCS is about twice that of people without HS.10

Squamous cell carcinoma (SCC) – A common form of skin cancer, SCC may occur occasionally inside or near HS lesions. The risk is higher on the buttocks and around the anal and genital areas. SCC affects men with HS more than women with HS.2,3

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Written by: Ina Fried | Last reviewed: December 2020