Fever, sweats, rash, sore throat, nausea, vomiting, myalgia, arthralgia, lymphadenopathy...

So the list of unpleasant side effects of cancer treatment parallels these tissue types: hair loss, skin rashes, nausea, vomiting, fatigue, weight loss, and pain.

Well for most adults, it's a relatively mild disease -- a little fever, a little headache, joint pain, maybe a rash.

Many patients acquire the allergy label as children, when a rash appears after they’re treated for an infection with penicillin or closely related drugs.

With these conditions, the body’s immune system attacks its own cells, a process analogous to a constant asthma attack or rash.

While an asthma attack, poison ivy welts, and irritable bowel syndrome might seem totally unrelated, they all have something in common: an immune response that’s doing more harm than good.