Food allergy is an immune system reaction that occurs soon after eating a certain food. Even a tiny amount of the allergy-causing food can trigger signs and symptoms such as digestive problems, hives , trouble breathing, or swollen airways. In some people, a food allergy can cause severe symptoms or even a life-threatening reaction known as anaphylaxis.

For some people, an allergic reaction to a particular food may be uncomfortable but not severe. For other people, an allergic food reaction can be frightening and even life-threatening. Food allergy symptoms usually develop within a few minutes to three hours after eating the offending food.

The most common food allergy signs and symptoms include:

It is important to see an allergist to help determine what food is causing the allergy, how to avoid the food, and when the food can be safely introduced. An allergist can also help formulate an action plan in case of accidental exposure to the food. 

Once food allergy has developed, the best way to prevent an allergic reaction is to avoid that food.