Long COVID occurs when symptoms—new, continuing, or recurrent—arise four or more weeks after the initial coronavirus infection.
Guillain-Barré syndrome is a neurological condition in which the immune system attacks healthy nerve cells.
Alopecia areata happens when the immune system attacks hair follicles. This causes the hairs in those follicles to fall out and not grow back.
Inflammatory bowel disease is the umbrella term for two conditions that cause chronic inflammation within the digestive system: ulcerative colitis and Crohn’s disease.