What causes allergic reactions?
Whether it’s runny, itchy or stuffed, your nose knows what’s bothering it. But do you know what’s wrong with your nasal passages? Understanding allergies isn’t difficult, but it is the first step toward building a healthy alliance with your nose, eyes, lungs, and sinuses. Allergies are the result of the immune system’s mistaken response to a harmless substance. Normally, the immune system stands guard and defends your body against intruders that can be dangerous to your health, such as viruses and bacteria. When it does its job well, your immune system keeps you from getting sick every time an ill-intentioned germ finds its way into your body. In some people, however, the immune system has difficulty distinguishing between the good guys (or, at least, the neutral guys) and the bad guys. Like a nervous rookie, it sees danger everywhere and overreacts. A hyperreactive i
