WebMD eHealth Tools
 |  |
 | |
Who's at risk?Developing AllergiesMore that one-fifth of Americans suffer from allergic diseases, with about 36 million suffering from seasonal allergic rhinitis, or hay fever. Some people inherit a tendency to be allergic to certain substances. To become allergic, however, a person must first be exposed to the allergen. This initial exposure sensitizes the immune system. A second exposure can then trigger the immune system to have an allergic response. Both a person's sensitivity and the amount of exposure to the allergen will affect the severity of the allergic response.
| |
| Copyright ® 2001 WebMD Corportation. All Rights Reserved | |
