July 26, 2013
Dear Mayo Clinic:
Is it possible for children to outgrow food allergies?
Some children may outgrow their food allergies. But the likelihood of that happening depends in large part on the type of food a child is allergic to, as well the severity of the allergy.
In people who have a food allergy, the body's immune system mistakenly identifies a specific food or part of a food as something harmful. When that happens, the immune system releases into the body immunoglobulin E, or IgE, antibodies. The next time the IgE antibodies sense that food, they cause a variety of chemicals, including histamine, to be released into the bloodstream.
Those chemicals trigger the symptoms of the food allergy, such as hives, skin or throat swelling, gastrointestinal problems, or breathing problems. In some people, a food allergy may lead to a life-threatening reaction known as anaphylaxis. Symptoms of anaphylaxis can include the above symptoms as well as severe tightening of the airways (causing breathing problems), rapid pulse, drop in blood pressure, and/or loss of consciousness. Without emergency medical treatment including epinephrine, anaphylaxis may result in death.
Food allergies affect about 6 to 8 percent of children under age 5, and about 3 to 4 percent of adults. Food allergies often are confused with a much more common reaction known as food intolerance. While bothersome, a food intolerance often is less serious. Usually, its symptoms come on gradually and are limited to digestive problems. Testing generally is not available for food intolerance. A severe form of food intolerance called food protein-induced enterocolitis syndrome, or FPIES, should be evaluated by an allergist or gastrointestinal specialist. Most children outgrow FPIES.
It is possible to have an allergic reaction to almost any type of food. But some foods lead to allergies more frequently than others. Of the common food allergies, milk, egg, soy and wheat allergies are the ones children most often outgrow by the time they are in their late teens.
About 60 to 80 percent of young children with a milk or egg allergy are able to have those foods without a reaction by the time they reach age 16. Recent studies suggest that children with egg or milk allergies who can eat those foods in a baked form, such as a muffin, without an allergic reaction are very likely to be able to tolerate plain egg or plain milk in the future.
Some other food allergies are much less likely to be outgrown. These foods are also common allergens and include peanuts, tree nuts, finned fish and crustacea. They tend to cause a more severe food allergy reaction. Only about 20 percent of children who have a peanut allergy outgrow it. An even lower number of those with tree nut allergies — 14 percent — will lose that allergy. And only 4 to 5 percent of children with a fish or crustacean (shellfish) allergy will go on to be able to eat those foods without a reaction later in life.
In many cases a blood test or an allergy skin test, combined with a thorough assessment of a child's health history, can help determine how likely it is for that child to outgrow his or her food allergy.
If it seems a child has outgrown a food allergy, a test called a food challenge may be recommended. It involves giving the child small amounts of the food in a controlled setting. A very small amount is given first. It is then doubled every 15 to 30 minutes until the child eats one serving size. This test is not recommended for children who are at high risk of anaphylaxis.
If your child has a food allergy, it is a good idea to work with a doctor who specializes in childhood allergies. An allergist can help you monitor and manage a food allergy over time as your child grows.
— Nancy Ott, M.D., Pediatric Allergy and Immunology, Mayo Clinic, Rochester, Minn.