allergies - general information

Your eyes are watery, your nose is itchy and runny, and you've got a throbbing headache from the pressure in your sinuses.

You're suffering from allergic rhinitis, and you're not alone. As many as 50 million people of all ages regularly suffer those same uncomfortable symptoms. They're caused by irritants called allergens-normally harmless substances that trigger overreactions in the immune systems of susceptible people.

Perennial allergies can occur year-round because they are caused by allergens in your living environment-often in your home. Allergies can also be caused by exposure to irritants such as paint fumes and cigarette smoke.

Pollens and molds are the main causes of seasonal allergic rhinitis (often called hay fever). In the United States, ragweed pollen prompts most seasonal symptoms. Grass and tree pollens are responsible for the rest.