The Connection Between Endometriosis and Other Health Conditions

Autoimmune conditions occur when the body's natural defense, the immune system, mistakenly attacks itself. Normally, the immune system identifies and attacks foreign invaders, germs, and other things that can harm the body, such as parasites, infections, and more. Instead of, or in addition to, attacking these, the immune system mistakenly attacks healthy cells and tissues by creating autoantibodies against itself and failing to function in the way that it should. The symptoms of an autoimmune disease can vary greatly depending on what condition an individual is diagnosed with. Treatment options also vary with diagnosis, and generally involve medications designed to relieve symptoms, suppress the immune system, or provide substances that the body may be lacking as a result of the autoimmune condition.¹

There are over 80 known types of autoimmune conditions, and more than one condition can co-occur at a time. Examples of autoimmune conditions include type 1 diabetes, celiac disease, Hashimoto's disease (underactive thyroid), inflammatory bowel disease, multiple sclerosis (MS), rheumatoid arthritis (RA), psoriasis, and systemic lupus erythematosus (SLE). Roughly 23.5 million people in America have at least one autoimmune condition, and women of childbearing age are more commonly affected than their male counterparts.¹

What are allergies?

Allergies are also immune system-related; however, they are characterized by the body's overreaction of the immune system against non-threatening substances. When a person has allergies, their body overproduces immunoglobulin E (IgE). IgE is an antibody that leads to allergic response symptoms including rashes, hives, sneezing, watery eyes, runny nose, or swelling of the mouth or throat. Most symptoms of an allergic reaction are irritating, but not life-threatening. However, symptoms like swelling of the mouth or throat may be indicative of anaphylaxis, which can be fatal if not treated in time. Allergies are thought to affect roughly 30% of all adults in America, and 40% of children.²

Treatment of allergies can vary from person to person, but may include medications like antihistamines, decongestants, corticosteroids (in the form of lotions or orally-administered medications), epinephrine (which often comes in a pre-filled injectable pen), or mast cell stabilizers. Immunotherapy options, such as allergy shots or sublingual immunotherapy (SLIT) are also potential treatment options. These involve exposing an individual to their allergens in small, but increasing, amounts.³ Common things that an individual might develop an allergy to are food, pets, pollen, latex, insects, or drugs. In some cases, an individual may be allergic to multiple things. Allergies are one of several atopic conditions. Atopic conditions are characterized by their overproduction of IgE, and include eczema (also called atopic dermatitis), allergic asthma, and allergic rhinitis.^2,4

What is fibromyalgia?

Individuals who have fibromyalgia experience widespread musculoskeletal pain, the hallmark symptom of the condition. This pain can be described as constant and like a dull ache on both sides of the body, above and below the waist. In addition to this pain, many individuals with fibromyalgia experience cognitive symptoms such as fatigue, as well as sleep, mood, and memory issues. The cause of fibromyalgia is unknown; however, some experts suggest that the pain is due to repeated nerve stimulation and changes in neurotransmitters (chemicals that may affect pain perception) in the brain. This repeated stimulation and change in neurotransmitter amount may cause nerves in the body to become more sensitive and constantly perceive and process pain.⁵

Fibromyalgia affects more women than men, and seems to run in families. Symptoms of fibromyalgia may build up over time, or they may occur suddenly after a trauma, infection, illness, significant stress, or a major medical procedure. Fibromyalgia often co-occurs with other conditions including certain autoimmune disorders, migraine, and irritable bowel syndrome. Diagnosis of fibromyalgia may be made after a pain point test to assess widespread pain or by taking a personal medical history that includes chronic, widespread pain for more than several months. Additionally, other exams and tests may be completed to rule out any other underlying condition. Treatment for fibromyalgia may include medications like pain relievers, anti-seizure medications, or antidepressants. Although individuals with fibromyalgia may not have depression or seizures, these medications are thought to help reduce pain. Treatment for fibromyalgia may also include physical or occupational therapy and counseling.⁵

How are autoimmune conditions, allergies, and fibromyalgia related to endometriosis?

The exact mechanism by which endometriosis is associated with autoimmune conditions, allergies, and fibromyalgia is not well understood, however, many studies have suggested that a correlation exists.^6-9 This means, although we don't know why, that those with endometriosis often also have at least one, if not more, of these additional conditions. The autoimmune conditions most often associated with endometriosis are systemic lupus erythematosus (SLE), inflammatory bowel disease (including Crohn's disease and ulcerative colitis), rheumatoid arthritis, Sjogren's syndrome, multiple sclerosis, and Hashimoto's thyroiditis (underactive thyroid).⁶

Since a proposed cause of endometriosis is an altered or faulty immune response that allows endometrial tissue to grow in other places within the body, some researchers suggest that this may be the key to the relationship between endometriosis and autoimmune conditions and allergies. Since both autoimmune conditions and allergies involve issues with immune system functioning, these issues may be the underlying link between these conditions. However, much more research needs to be completed for this hypothesis to be strengthened, especially since an immune system-related issue is only one of many potential contributing factors to the development of endometriosis.^6-8

As far as endometriosis and fibromyalgia, this link is even less understood. Across many studies it has been apparent that women with endometriosis more commonly have co-occurring fibromyalgia than women without endometriosis, however, the reason for this is unclear.^6,9 One potential hypothesis is that the chronic pain experienced by women with endometriosis may be a precursor to, or trigger for, fibromyalgia.⁶ However, since the root causes between both endometriosis and fibromyalgia are not well characterized, determining why the two seem to be linked has yet to receive an adequate answer.