If you encounter an unpleasant reaction after eating certain foods - hives, itching, swelling or trouble breathing - you may have a food allergy. Then again, you might not.
Less than 2 percent of adults and 8 percent of children actually have a true food allergy. This is little consolation if you've had a bad experience and fear a recurrence. That's why it's important to distinguish a food allergy from more common problems such as food intolerance, indigestion or other conditions.
If your reaction to a certain food becomes more than an inconvenience or the symptoms are severe, talk with your doctor. Tests can help diagnose food allergies, and you can take precautions to help prevent serious and even life-threatening responses to consuming culprit foods.
Signs and symptoms
Reactions to certain foods are uncomfortable for most people, but for others they are frightening and possibly life-threatening. Symptoms of a food allergy usually develop within an hour of eating the offending food.
The most common signs and symptoms of a true food allergy include:
In a severe allergic reaction to food, you may have more extreme versions of the above reactions, or you may experience the following life-threatening signs and symptoms:
These signs and symptoms constitute a rare but life-threatening allergic reaction known as anaphylactic shock.
A true food allergy involves your body's immune system response to a specific food or component of a food. Your immune system produces immunoglobulin E (IgE) antibodies to fight against even a tiny amount of the culprit food or food component (the allergen). This in turn releases histamine and other chemicals that cause the distressing signs and symptoms that may be a threat to life. Histamine is partly responsible for most allergic responses, including dripping nose, itchy eyes, dry throat, rashes and hives, nausea, diarrhea, labored breathing and even anaphylactic shock.
The great majority of food allergies are triggered by certain proteins in:
Beans and corn also commonly cause food allergies. Chocolate, long thought by some parents to be a culprit among children, seldom is a cause of allergy.
Other reactions to food don't involve your immune system or, consequently, the release of histamine. These reactions aren't true food allergies. Instead, they may be food intolerances. Because food intolerances may involve many of the same signs and symptoms as food allergies do — such as nausea, vomiting, cramping and diarrhea — people often confuse the two.
If you have a food intolerance, you usually can eat small amounts of problem foods without a reaction. By contrast, if you have a true food allergy, even a tiny amount of food may trigger an allergic reaction.
Common causes of food intolerance include:
One of the tricky aspects of diagnosing food intolerance is that some people are sensitive not to the food itself but to a substance or ingredient used in the preparation of the food. This is especially true of foods containing lactose, wheat or sulfites.