9 common allergies explained
Tue, Jan 11, 2011 at 5:47 AM
About one out of every five Americans suffers from allergies, which are exaggerated immune responses to harmless substances. The immune system typically protects the body from viruses and bacteria, but a person with allergies has an overly sensitive system that releases chemicals such as histamines — which can cause symptoms like itching, swelling and hives. Here’s a look at some of the most common types of allergies — from milk to pet dander — and how to cope with them.