Autoimmune diseases happen when your body’s immune system starts attacking its own organs, tissues, and cells. Although they’re on the rise, they’re also tricky to diagnose. Symptoms can creep up slowly, and many of them—like achy joints, fatigue, and tummy troubles—overlap with other disorders.
But there’s one symptom that many autoimmune diseases share: weight changes. “Almost everyone with an autoimmune disorder has it affect their weight one way or the other,” says Mark Engelman, MD, a clinical consultant for Cyrex Laboratories, a clinical lab specializing in functional immunology.
So if the number on the scale suddenly goes up or down with no good explanation, take stock of whether you’ve experienced any other weird, nagging symptoms, and talk to your doctor if you think an autoimmune disease could be to blame.