Endometriosis is a complex and chronic condition that affects more than 10 percent of women of reproductive age. Despite its prevalence, the pathogenesis of endometriosis (underlying physical cause) is still poorly understood. Endometriosis shares many features with other complex chronic diseases, including autoimmune diseases.

What Is Endometriosis?

Endometriosis occurs when endometrial tissue that normally lines the inside of the uterus, grows in abnormal locations outside the uterus, including the ovaries, fallopian tubes, and other organs in the abdomen and pelvis.

Common symptoms of endometriosis include:

• Chronic abdominal and pelvic pain
• Painful menstruation
• Bloating
• Pain during intercourse (dyspareunia)
• Infertility

Endometriosis is affected by changes in estrogen levels, so the severity of symptoms can vary throughout the menstrual cycle. A diagnosis of endometriosis can be suspected based on symptoms and examination but can only be confirmed surgically, using laparoscopy. Treatments for endometriosis can include surgery to remove lesions and adhesions, contraceptives to lower estrogen levels and control ovulation, and, in severe cases, hysterectomy. Endometriosis has many comorbidities, including autoimmune diseases.

What Are Autoimmune Diseases?

Autoimmune and autoinflammatory diseases are conditions where the immune system attacks the body, treating otherwise healthy tissue as if it were an infection or cancer. Autoimmunity only describes conditions that cause the body to produce autoantibodies — antibodies that target proteins that are a normal part of the body (also called self-proteins). Autoinflammation refers to conditions that cause the immune system to damage healthy tissue by causing inflammation.

More than 80 different autoimmune disorders have been identified, including:

• Rheumatoid arthritis
• Multiple sclerosis
• Systemic lupus erythematosus
• Inflammatory bowel disease (Crohn’s disease and ulcerative colitis)
• Type 1 diabetes

Autoimmune disorders can be systemic, causing an immune response throughout the body (lupus), or localized to specific organs (like vitiligo, which affects the skin). The causes of autoimmune and autoinflammatory disorders are not fully understood, but genetic and environmental factors play a role.

Is Endometriosis an Autoimmune Disease?

To put it simply, no, endometriosis does not appear to be an autoimmune disease. However, it is associated with a higher risk of having several autoimmune disorders, as well as a host of other chronic medical conditions. Research has found links between endometriosis and rheumatoid arthritis, inflammatory bowel disease, lupus, multiple sclerosis, Sjögren’s syndrome, and celiac disease.

Endometriosis shares several important features with autoimmune diseases, including chronic pain, chronic inflammation, and immune system dysfunction. Having both autoimmune disease and endometriosis is also associated with more severe endometriosis. Another connection between autoimmune disease and endometriosis is a specific mutation of the PTPN22 gene, a gene mutation linked to many different autoimmune conditions as well as endometriosis.

What Does This Mean for People With Endometriosis?

Understanding how endometriosis and autoimmune diseases are related is very important for endometriosis research, but how can this information help people with endometriosis? Knowing that autoimmune diseases have been identified as a comorbidity with endometriosis can help individuals with endometriosis and their doctors be aware that a diagnosis of one condition may increase the risk of the other.

Understanding that diseases can be related or comorbid can encourage you and your health care providers to look for answers beyond your diagnosis, especially when symptoms do not respond to treatment for the diagnosed condition.

Talk With Others Who Understand

MyEndometriosisTeam is the social network for people with endometriosis. On MyEndometriosisTeam, more than 122,000 members come together to ask questions, give advice, and share their stories with others who understand life with endometriosis.

Are you or someone you care for living with endometriosis? Share your experience in the comments below, or start a conversation by posting on your Activities page.