Symptoms, triggers, diagnosis and prevention. Food reactions among children have become increasingly common over time. Such reactions can be caused by either food allergy or food intolerance. It can often be difficult for parents to tell the difference. Both types of reactions have similar symptoms: stomach discomfort, nausea, vomiting or diarrhea. A food allergy can be more serious, however.
According to the Centers for Disease Control and Prevention (CDC), food allergies affect about four percent of children, although some outgrow them. A true food allergy is an immune symptom response to a food whereby the body mistakes an ingredient in food (usually a protein) as harmful and creates an army of defense within its immune system (antibodies) to fight it. An allergic reaction occurs when that army of defense fights with the unwelcome food ingredient.
Food intolerance is a digestive system response whereby a child has difficulty digesting certain foods for a variety of reasons, but there is no involvement of the immune system in the reaction. Food intolerance is also commonly referred to as food sensitivity.
Any food can trigger an allergic response, and more than 170 foods have been reported to cause immune system reactions. Eight foods have been identified as causing 90 percent of food allergies: peanuts, tree nuts, fish, shellfish, milk, soy, wheat and eggs. The protein structure within a food is altered when you cook or bake it, and this influences how reactive a child may be to that food. For example, some egg-sensitive children may be able to tolerate eggs in baked products (e.g., cookies), but not when eaten alone. Or children with a milk allergy may be able to tolerate baked macaroni and cheese, but cannot drink milk alone. Allergies to milk, eggs, wheat and soy generally resolve more quickly in childhood than allergies to peanut, tree nuts, fish and shellfish do.
The causes of food intolerances can vary widely and include any difficult digestive issues the child may have. Conditions associated with food intolerance include lack of digestive enzymes, irritable bowel syndrome, food poisoning, sensitivity to food additives, recurring stress or psychological factors and celiac disease. All of these conditions, while similar, have different mechanisms causing symptoms of food intolerance. The most common food intolerance is caused by lactose, a milk protein. Children with lactose intolerance lack the enzyme necessary to digest milk and find a lactose-free alternative such as soy or almond milk to be a good choice.
Food intolerance symptoms generally come on gradually, while food allergy symptoms tend to have a faster onset (see Common Symptoms of Food Allergy and Food Intolerance). Both types of reactions Any food can trigger an allergic response can be affected by the amount of problematic food a child eats. For example, a child who has gluten intolerance may be able to eat a small amount of gluten-containing foods without a problem, but the child would exhibit symptoms if she ate such foods at all three meals in a day.
Diagnosing Food Allergies and Intolerance
If you are concerned your child may have a food allergy, schedule an appointment with an allergy specialist for evaluation and testing. Food allergies are diagnosed by having a positive skin prick test or blood test and a positive challenge diet. The provider will take a detailed medical history of your child’s food reactions at this appointment. Be prepared to discuss important aspects of your child’s food reaction such as: (1) the possible provoking foods, (2) the form or forms in which the food was ingested (raw, semi-cooked, cooked or baked), (3) the quantity ingested, (4) the timing of reactions and (5) the nature of reactions.
Food allergies are fairly predictable, and uncommon reactions suggest an alternative diagnosis. It’s not common for a child to have a food allergy to a food he is now eating without a problem, though previously he had reported having a reaction to it. For example, if your child had a reaction to chocolate in the past but now frequently eats it without any problems, he is likely not allergic to chocolate.
Food intolerance is diagnosed by your child’s experiences eating the food and a detailed medical history. There are no specific tests to diagnose food intolerance. As with diagnosing a food allergy, you may be asked to start a food challenge diet as a part of the diagnostic process. If the symptoms recur when the food is eaten as a part of a challenge diet, a diagnosis is made.
Preventing Food Reactions
Parents can take a few simple steps to help minimize their child’s risk of food reactions. Identifying which foods trigger symptoms is the place to start. You will want to avoid your child’s intake of those foods that cause symptoms, as there is no other cure for food allergies or intolerance. When you and your child eat in a restaurant, it’s important to ask questions about the food ingredients and preparation. Be wary of possible cross-contamination of foods. You will need to learn how to read food labels and check the ingredients lists for problem foods with every purchase. Also check seasoning and condiment food labels.
A child who has a food allergy may be at risk for a life-threatening allergic reaction called anaphylaxis. Even if past reactions have been mild, food-allergic children are always at risk for anaphylaxis. It’s important to learn how to recognize a severe allergic reaction, and what to do if one occurs.
Karen S. Rance, DNP, RN, CPNP, AE-C, is an allergy, asthma and immunology specialty NP at Allergy Partners of Central Indiana, Indianapolis. Dr. Rance is adjunct faculty at Indiana Wesleyan University, Graduate School of Nursing. She also serves on the Board of Directors of the National Association of Certified Asthma Educators, the National Asthma Education Prevention Program Expert Panel workgroup and NAPNAP’s