It's one of medicine's biggest mysteries — why sometimes our immune system attacks our own bodies. Autoimmune diseases affect ...

Picture this: one tiny red bump from a summer hike. You slap on some cream, forget about it. Two years later, that same spot is a stubborn rash that’s spread across your arms, your face, your life.

That stubborn spot on your face that refuses to go away may just not be that usual pimple, after all. Every year, millions ...