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9 common allergies explained

By: Laura Moss on Jan. 11, 2011, 5:47 a.m.
woman sneezing

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Bless you

About one out of every five Americans suffers from allergies, which are simply 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. (Text: Laura Moss/MNN)