Sore joints, eczema, headaches, low energy, digestive issues—if you suffer with any of these on the regular, you're probably tempted to brush them off as annoying but not that big of a deal.

Yet if your symptoms are chronic or don't have an obvious cause (like a gnarly workout that you can link to muscle aches), one doctor warns you shouldn't take them lightly because they could be hints that a more serious health storm is brewing.

According to Parsley Health founder Robin Berzin, MD, all of these complaints could be early signs of autoimmune disease: a broad category of ailments that are plaguing a rapidly growing number of Americans, especially women. (According to the National Institute of Allergy and Infectious Diseases, almost 80% of people with autoimmune disorders are female.)

In her own integrative medical clinics in New York City and Los Angeles—the latter of which just opened this month—Dr. Berzin says that the number of patients she's seeing with autoimmune issues is growing at an alarming rate. "What we're seeing is that our immune systems are becoming increasingly dysregulated," she says. "Ulcerative colitis, Crohn's, Hashimoto's [disease]—autoimmune diseases of all kinds are on the rise."

If you've heard the term before but don't know exactly what it means, you're not alone. Autoimmune disorders as a group are nearly as common as cancer and heart disease, but they're talked about way less.

As Dr. Berzin explains: "An autoimmune disease is when the immune system, which is only supposed to attack outside invaders, starts attacking the cells in your body." For instance, rheumatoid arthritis occurs when immune antibodies attack the joints, leading to serious pain and swelling; Hashimoto's disease is an autoimmune thyroid condition, which eventually causes fatigue, depression, and weight gain (among other symptoms); while for those with ulcerative colitis and Crohn's disease, the intestinal tract becomes severely inflamed.

Not only are these illnesses not as rare as you may think (statistics from the US Department of Health and Human Services say that autoimmune disorders affect 23.5 million Americans, and that women of childbearing age are the most commonly afflicted), but they're also affecting a wide range of women, celebrities included—Selena Gomez has very publicly battled lupus, an autoimmune disease that affects the entire body, while Zoe Saldana and Gina Rodriguez recently revealed that they have Hashimoto's.

Why are so many of our bodies turning against us—and what can we do about it? Head over to Well + Good to keep reading about the key things to know about autoimmune disorders, plus tips on how to help reverse the symptoms naturally.