Many day cares and preschools in the U.S. have prominently posted signs asking parents not to pack food for their kids containing peanuts, because so many children are allergic. It seems like special dietary needs are an ever-growing issue.
Food allergies affect as many as 8% of children in the U.S., leaving a challenge for parents: What can you pack for lunch? How can you be sure your kids don't trade snacks with a friend? How should you handle occasions like birthday parties?
To find answers -- for causes, symptoms, diet, and more -- WebMD talked to Wesley Burks, MD, chief of the division of pediatric allergy and immunology at Duke University Medical Center.
Fast Facts About Food Allergies
Q. What are the most common food allergies in children?
A. Of the 6% to 8% of children below school age who have a food allergy, the majority are allergic to eggs, milk, and/or peanuts. Milk allergies affect about 2.5% of children, egg allergies affect 1.5%, and peanut allergies about 1%.
Other food allergies that become more common as kids reach school age are allergies to wheat and soy, shellfish, fish, and tree nuts.
Q. Do children outgrow food allergies?
A. By the time they're about 7 years old, most kids outgrow allergies to milk, wheat, and soy, but they generally do not outgrow peanut and tree nut allergies and allergies to fish and shellfish. Be aware of what allergies might be outgrown, and continue to go back to seek medical care as your child gets older to see if he or she might no longer be allergic.
Q. What predicts the severity of a food allergy?
A. There's no test that will predict the severity of a reaction. The amount of IgE antibodies produced doesn't correlate with how severe a reaction is. [Immunoglobin E antibodies (IgE) are produced in excess by allergic people.] At one point, a child may have a severe reaction, and another time, it may be much less severe. It could be due to the amount of the food they ate, whether or not it was an empty stomach, if they already had a viral infection -- all kinds of factors.
Q. What other kinds of food sensitivities are there?
Lactose intolerance is not typical in young children. It happens more in adults, and when we do see it in children, it's more in school-age kids than in babies and toddlers. Lactose intolerance is caused by the relative lack of an enzyme that helps to digest the lactose in the milk product. Because it's not caused by the immune system, it just involves gastrointestinal symptoms like abdominal pain, bloating, diarrhea, and sometimes vomiting. It's really related to how much milk you ingest and is usually fairly manageable.
It takes a fairly large amount of lactose to cause significant symptoms, like about a glass of milk on an empty stomach. Management is just avoiding lactose-containing products to a significant degree.
Gluten sensitivity is also not an IgE-mediated allergy. It's caused by a T-cell in the body that reacts to gluten proteins. (Gluten is a highly complex protein found in wheat, rye, barley, and oats, and therefore in baked goods made from these grains, like bread, cookies, and pizza.) Again, it's more seen in adults and is relatively uncommon in children, and the typical symptoms are gastrointestinal -- you don't have the hives and wheezing you see with a classic wheat allergy.
Food Allergies: Causes, Symptoms, Diagnosis, and Treatment
Q. What causes food allergies?
A. A true allergic reaction to a food is produced by a mistaken immune response. These are called IgE-mediated allergies, because they are triggered when immunoglobulin E antibodies are produced in response to a specific food the child is sensitive to.
There are also other food sensitivities and reactions that are not IgE-mediated. For example, some young children have a condition called enterocolitis, an intestinal inflammation. In these cases, they have gastrointestinal symptoms after ingesting milk or soy formula, but no respiratory or skin symptoms. These are not IgE-mediated allergies, and kids usually outgrow this condition by age 2 or 3.
Q. What are the symptoms of a food allergy?
A. Food allergy symptoms include skin, gastrointestinal, and respiratory symptoms. Skin symptoms include hives or an itchy red rash; respiratory symptoms include coughing, wheezing, and laryngoedema (a swollen throat); and the gastrointestinal symptoms include significant vomiting, intestinal pain, and diarrhea.
These symptoms are always temporally related to ingestion -- that means, very close in time. Often it's seconds to minutes after ingestion, but always within hours. If you drink milk today and have symptoms tomorrow, it's not related.
Q. How are food allergies diagnosed?
A. An allergist or primary care provider can do allergy testing. They will run either a skin test or draw blood, and in either sample, they'll look for IgE antibodies to particular foods. If there are no IgE antibodies to the foods, the child is likely not allergic.
Q. How do I treat a food allergy?
A. The only way to treat a true food allergy is to avoid the food in question.
Food Allergies: A Safe and Healthy Diet
Q. If my child has special dietary needs, how do I replace in their diet the foods they can't eat?
A. Generally, milk and egg allergies are fairly manageable. For example, you can boost your child's calcium intake with calcium-enriched orange juice and supplements, and there are ways to make egg-free foods. Wheat and soy are more problematic, because soy, in particular, is in so many foods.
Some of the best tools to help you replace these foods in your child's diet (and to know what's in the food you're shopping for) are from the Food Allergy and Anaphylaxis Network (FAAN) (http://www.foodallergy.org/). They have sample recipes on their web site, and several great cookbooks, as well as tips for shopping and cooking, notices about changes in ingredients to particular foods, and resources for understanding food labels.
Q. How can I make sure my child with special dietary needs eats safely at school, in restaurants, and at parties?
A. Have a healthy respect for the allergy. Don't live in fear of what they're going to eat, but don't be cavalier. Help the child to know that it really takes ingestion of the food, for the most part, to cause a life-ending reaction -- not smelling or touching, it's ingestion. If you're on an airplane, it can be different because the air is recirculated, but at the park or in a restaurant, it's not going to harm your child if someone opens up a jar of peanut butter.
Make the allergy part of who they are, and help them avoid it appropriately, but don't overly dramatize what kind of symptoms they might have. It's not any different than teaching them not to stick their hand in the oven, and other things that can be harmful for them.
FAAN also has a great section for kids at http://www.fankids.org/. There, they can learn about the basics of food allergies, try recipe "projects" with replacements for the foods they're allergic to, and hear from other children with food allergies. This helps give them the tools to eat safely even when you're not right there with them.
Q. Does a milk allergy mean my child is lactose intolerant?
A. No. Childhood milk allergies are very different from lactose intolerance. Many kids outgrow their early milk allergies by school age. In the meantime, treatment can be the elimination of milk-containing proteins from the diet -- like milk, cheese, and ice cream. Depending on the child, to get the needed proteins, a substitute such as soy formula or a hypoallergenic formula like Alimentum can be used.
Q. What do I do if my child accidentally eats a food he's allergic to?
A. In some very severe cases, parents and children carry what's called an Epi-Pen, an automatic injector of adrenaline that can immediately treat anaphylactic shock in response to exposure to a food the child is allergic to. But this is only necessary in those children who've had previous severe allergic reactions, those with significant asthma, and those who are allergic to peanuts, tree nuts, fish and shellfish. Those allergies are the ones that most commonly cause severe reactions. If your child has a milk allergy and has never had a really severe reaction, and doesn't have asthma, you don't need an Epi-Pen. For that particular child, your doctor might simply prescribe antihistamines.
Food Allergies: Pregnancy and Family
Q. Should I avoid highly allergenic foods like peanuts or shellfish when I'm pregnant or nursing?
A. Many people will say to avoid these foods while nursing and as part of the child's diet during the first three years, but the evidence for that is less than what we'd like. I don't know the right answer.
Q. What about my next child? What are the chances they'll have special dietary needs?
A. If no immediate family member -- a parent or sibling -- has allergic disease, the risk of a child's developing any allergy is about 20%. If one family member has allergic disease, the risk is about 40%, and if two members are, there's about a 60% risk. Allergic disease is inherited as allergic disease, not just as food allergies. For example, if you have a milk allergy, your child might have asthma, and vice versa.
We do know that breastfeeding for more than four to six months, and avoidance of solids for at least the first four to six months, is best for avoiding allergies in children who are at increased risk because of allergies in their family. (If your child is not high-risk for allergies, breastfeeding still has clear benefits, but there are no known benefits specifically in preventing allergies.)