What Causes Allergies?

What is an allergy and why are allergies the most common reason for missing school? More than 50 million people have some kind of bout with allergies, either seasonal (such as hay fever) or perennial (such as an allergy to pet dander or peanuts), and allergy medications are a booming business, with more than 10 billion dollars spent on allergy medications each year. What Causes Allergies? is a timely book that covers the different types of allergies, how allergies affect the body, the kinds of treatment available for allergy sufferers, and much more.