A food allergy is an abnormal
response to a food by your immune system. Normally, the immune system protects
your health by defending the body against harmful bacteria and viruses. With a
food allergy, the immune system identifies certain foods as harmful and
triggers an allergic reaction when you eat them.
are more common in children than adults. Food allergies are most common in
people who have an inherited tendency to develop allergic conditions. These
people are more likely to have asthma and other allergies.
allergies may appear in a baby when you begin to add cereal to the baby's diet.
Children tend to outgrow many food allergies by age 3. The most common foods
involved are cow's milk, eggs, nuts, shellfish, soy products, and wheat. Most
people who have allergies to seafood, eggs, peanuts, and tree nuts do not
Symptoms of food allergies can range from mild and
annoying to severe and life-threatening. Symptoms of food allergies can begin
right away or within a few hours and can include:
A severe allergic reaction (anaphylaxis), which can occur suddenly and quickly
become life-threatening. Anaphylaxis can cause wheezing or difficulty
breathing, rapid swelling of the throat or tongue, hives, nausea or vomiting,
and faintness. In general, the sooner the reaction begins, the more severe it
will be. Call 911 or other emergency services immediately if you are having a severe allergic
Swelling and itching of the mouth, tongue, or
reactions, such as nausea, vomiting, diarrhea, stomach cramps, rectal itching,
You may be able to prevent food allergies by changing
your diet and not eating the foods that you suspect are causing your symptoms.
Do not eat these foods for 2 weeks. Add the foods back to your diet, one item
at a time, to determine which food is causing problems. This can be done at
home unless severe allergic reactions have occurred in the past, such as
difficulty breathing or wheezing, facial swelling, itching of the lips or
mouth, or hives. If this is the case, eating foods that you think may cause a severe reaction should be done only
in a clinic or hospital setting under direct medical supervision.
Talk to your doctor or a dietitian before you remove a food
from your diet for more than 2 weeks. An unbalanced diet can be harmful. A
dietitian can help you change your diet to make sure you are getting proper
Reactions to food
Some reactions to foods are not
caused by allergies. Common causes of food reactions include:
Lactose intolerance. This is an inability to digest sugar
(lactose) in dairy products because a person's body doesn't have the chemical
(enzyme) that breaks down the sugar. Lactose intolerance causes stomach or
intestinal cramps and diarrhea.
Chinese restaurant syndrome (CRS).
Monosodium glutamate (MSG), a seasoning that is often used in Asian cooking,
may cause dizziness, sweating, ringing in the ears, and a feeling of faintness
in some people shortly after they have eaten foods that contain
Wheat intolerance, such as
celiac disease. Children are more likely than adults
to have trouble digesting foods that contain wheat, such as bread, crackers,
and cereal. These foods are likely to cause them to develop gas.
How this information was developed to help you make better health decisions.