An allergy is an immune system response to a foreign substance that’s not typically harmful to your body. These foreign substances are called allergens. They can include certain foods, pollen, or pet dander. Allergies are common. Several treatments can help you avoid your symptoms.

The symptoms you experience because of allergies are the result of several factors. These include the type of allergy you have and how severe the allergy is.

If you take any medication before an anticipated allergic response, you may still experience some of these symptoms, but they may be reduced.

Researchers aren’t exactly sure why the immune system causes an allergic reaction when a normally harmless foreign substance enters the body.

Allergies have a genetic component. This means parents can pass them down to their children. However, only a general susceptibility to allergic reaction is genetic. Specific allergies aren’t passed down. For instance, if your mother is allergic to shellfish, it doesn’t necessarily mean that you’ll be, too.