Autoimmune diseases occur when the immune system, which is meant to defend your body, actually attacks it. These disorders affect more than 23.5 million Americans, according to the National Institute of Environmental Health Sciences, and they are far more likely to affect women than men.

More than 80 autoimmune diseases have been identified, and we’ve listed the symptoms of some of the most dangerous.

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GRAVES’ DISEASE

This autoimmune disease is caused by overactivity of the entire thyroid gland. According to the American Thyroid Association, symptoms of Graves’ include hyperthyroidism, eye disease, and skin problems.

If Graves' disease isn't treated, it can lead to life-threatening complications. Everyday Health reported that these health issues include heart problems, a thyroid storm (where heart rate, blood pressure and temperature can rise to dangerous levels), pregnancy problems, and osteoporosis.

GIANT CELL MYOCARDITIS

A 2000 study from researchers in New Jersey found that giant cell myocarditis (GCM) is the most fatal autoimmune disease. It is uncommon and characterized by inflammation of the heart muscle, according to the National Organization for Rare Disorders.

Initial symptoms of GCM may include swelling of the ankles, chest pain, heart palpitations, fatigue, and shortness of breath.

ADDISON’S DISEASE

One classification of Addison’s Disease is called Primary Adrenal Insufficiency, which is where your immune system attacks the body’s adrenal glands. Healthline reported that these glands are located on top of your kidneys, and they produce many of the hormones that your body needs for normal functions.

Symptoms include weakness in the muscles, fatigue and tiredness, darkening in skin color, and a decrease in heart rate or blood pressure.

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GRANULOMATOSIS WITH POLYANGIITIS

This disorder (previously called Wegener’s Granulomatosis) causes inflammation of the blood vessels in your nose, sinuses, throat, lungs and kidneys — but is pretty rare. According to the Mayo Clinic, it actually slows blood flow to some of your organs.

Symptoms of granulomatosis with polyangiitis may include numbness in limbs, blood in urine, coughing bloody phlegm, skin sores or bruising, fever, fatigue, and shortness of breath.

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