Unfortunately, the prevalence of allergic diseases (such as food allergy, asthma, eczema, hay fever) appears to be increasing. In particular, it seems that the number of people diagnosed with food allergy is increasing. About 6 percent of young children have food allergies, along with nearly 4 percent of adults. Whether this increase in incidence is due to a better understanding of the disease, better methods to make a diagnosis or a true increase in the number of people with food allergy is not totally clear.
Can you outgrow an allergy?
There are certain foods that infants and young children tend to be allergic to: milk, egg, wheat, soy, and – as they grow a bit older – peanut, tree nuts, fish and shellfish. Fortunately, most children outgrow milk and egg allergies by 2 or 3 years old. However, with peanut allergy, some children may develop it later in life, or may develop allergy to it during adulthood. Once peanut allergy is developed, about 20 percent of people may “outgrow” it. We don’t yet have a clear understanding of who will likely outgrow a peanut allergy (as we do for those who outgrow foods like milk and egg), but it is probably those people who have a low blood level of the allergic antibody, IgE, to peanut.
The Problem with Peanuts
The problem with peanut allergy is that it can be life-threatening, probably more so than food allergy to milk and egg. To make things worse, even small amounts of peanut proteins can be found in foods such as ice cream, cookies and candy – even if they don’t say “peanut” on the label. This is because in food processing plants, some foods may be processed on the same lines as foods that have peanuts. Or at restaurants, if a utensil is used that was also used to serve a dish with peanuts, it may “contaminate” another dish. Fortunately, recent legislation has mandated that food labels be made clearer to the public about the contents of the food - specifically, whether the food may contain peanuts or other allergic foods.
Peanut Allergy Prevention: Is it possible?
How to “prevent” the development of peanut allergy is a difficult question. The American Academy of Pediatrics recommends that peanut not be introduced into a child’s diet until at least the age of 3 years. The reason is that the child’s immune system may not be fully developed before 3 years, and giving the child peanut butter beforehand may lead to development of peanut allergy. However, this is just a theory – and one may argue that giving peanut butter every day may cause the child to be “tolerant.”
It is important to note that if a mother is breastfeeding and eating peanuts, the peanut proteins may enter her milk and her baby as well. That said, those children at risk for allergic diseases (for example, the parents with a history of allergies, or a sibling with allergies), may potentially benefit or be protected against developing allergies by breastfeeding (in mothers who avoid peanut, tree nuts, and other allergenic foods) up to one year of age.
This idea, however, is controversial – several studies support the theory, and others argue against it. Some studies have even suggested feeding infants formulas that are completely hydrolyzed, meaning processed to destroy milk and soy proteins to be “less allergenic.” This, too, is controversial. For pregnant women, it may also be a good idea to avoid eating peanuts, especially in the 3rd trimester. Again, this is not proven, and some studies will show that eating peanuts during pregnancy may help prevent peanut allergy.
Bottom line: we suggest to try to avoid the introduction of peanut into the child’s diet until after the age of 3 years old.
Testing for Allergy
Once a peanut product is given to a child, there are several ways to determine if he or she is allergic to it. After a child eats peanut, watch for food allergic symptoms such as hives, vomiting, diarrhea, shortness of breath, wheezing. The symptoms usually will develop shortly after eating. If this occurs, contact a pediatrician immediately. It may be necessary to bring the child to the emergency room, or to give the child liquid anti-histamine at home. An allergist can then determine if the reaction is due to peanut by either a blood test or a skin test, or he or she may do both. If your child has peanut allergy, it is critical to strictly avoid peanut and have emergency medication at home, school or with any care takers. Anyone who cares for your child needs to be aware of the food allergy symptoms and how to treat them.
To determine if your child outgrows the peanut allergy, DO NOT give peanut to the child at home to test. Only the allergist can help you determine if your child may have outgrown peanut allergy, and he or she may give the child peanut in a hospital or office. If you have further questions, please let me know. Another good resource is the Food Allergy Network.