Common Causes – Food
Any food may cause an allergic reaction, but 90% of food allergies are caused by just 6 common foods or food groups—milk, eggs, peanuts, tree nuts, soy, and gluten. Unfortunately, there are other cross-reactant foods that, when someone is sensitive to gluten (the MOST common food antigen), they can equally react to:
Allergy to cow’s milk is among the most common hypersensitivity in young children, probably because it is the first foreign protein that many infants ingest in such a large quantity, especially if they are bottle-fed. If there is a cow’s-milk allergy, occasionally even a breastfed infant may have colic or eczema until milk and dairy foods are eliminated from the mother’s diet. Between 2 and 3 out of every 100 children younger than 3 years have allergy symptoms linked to cow’s milk.
Vomiting after feeding is the most common way a child shows a milk allergy, but more severe reactions can occur. Colic, crying, and gassiness can sometimes be the only manifestation of cow’s-milk allergy in very young infants. (It must be said, though, that in the great majority of infants, no cause for colic is ever found, and the inconsolable crying eventually stops without treatment, never to return, before the baby is 6 months old). Other early and more subtle symptoms of milk allergy often involve the itchy, dry rash of eczema (atopic dermatitis). Of course the most obvious kind of reaction to milk is when the child drinks milk or eats a milk product and immediately develops breathing problems or hives. Most children with cow’s-milk allergy are also allergic to milk from goats or sheep, so these are not good substitutes.
Soy-based formula are NOT suitable for milk-allergic infants because some who are sensitive to cow’s milk are also unable to tolerate soy protein.
People who are allergic to eggs are reacting primarily to the protein in the egg white. However, because egg yolk can often be contaminated with egg white, it’s safer for egg-allergic children to avoid egg altogether. Luckily, while eggs are nutritionally valuable and an excellent source of protein, they are not essential for good nutrition. Meat, fish, dairy products, grains, and legumes are excellent alternative sources of similar protein, minerals, and vitamins.
Peanuts and Tree Nuts
When is a nut not a nut? When it’s a legume—like peanuts, which are cousins to peas and beans. Because peanuts and tree nuts come from different plant families, a child who is sensitive to peanuts can often eat walnuts, pecans, and other tree nuts without a problem. However, caution is needed because peanut-allergic children, for unknown reasons, are more likely also to have a separate tree-nut allergy.
Like eggs, peanuts are delicious and nutritious but not essential for a healthy diet. No nutritional substitutes are needed. Most people with a peanut allergy tolerate other legumes such as soy and beans, even when sometimes skin or blood tests will come up positive for these other legumes.
Peanuts, although generally pretty easy to avoid, can sometimes show up in foods when least expected. Peanuts are often ground up and used as bulking agents in food products such as candies. Peanut butter is sometimes used by restaurants and caterers as a “glue” in food preparation to hold the food item together. Therefore, it is imperative that you not only read labels carefully to make sure peanuts are not unsuspected ingredients in commercial foods, but that you also question and clarify the content of food being bought and eaten at restaurants, or prepared and consumed at locations other than your own house.
Allergy to tree nuts—walnuts, pecans, cashews, Brazil nuts, almonds, hazel nuts; all the nuts in hard shells—can be as severe as peanut allergy, and the same warnings apply. One child may have an allergy to only one tree nut, while another may have an allergy to a number of tree nuts. Confusion can sometimes occur about the different types of tree nuts, so tree-nut–allergic individuals often just stay away from all of them, to play it safe. Make care-givers, teachers, friends, and family members aware that your child must strictly avoid all products with even a trace of nuts and peanuts because nut allergy, in general, is the most severe of all the food allergies.
Babies fed soy formula, like that of cow’s milk, can develop a rash, runny nose, wheezing, diarrhea, or vomiting from allergy to the soy protein. When changing to a soy formula, some infants who are allergic to cow’s milk are found to also be allergic to soy. If this is the case, we may recommend a low-allergenic formula made with extensively hydrolyzed protein or amino acid elemental formula.
Wheat and Gluten
Rice and oats are usually the first cereals introduced into the diet because they are less likely than other grains to cause allergy problems. If there are no problems with oats, wheat is given next. Wheat is the grain most often associated with allergies, but even so, it is still an uncommon food allergy. This is fortunate because wheat is found in so many prepared foods.
There are 2 types of negative immune reactions to wheat. The first is classic food allergy, with symptoms such as hives or wheezing that occur immediately after the child eats a food made with wheat. The second is called celiac disease. Gluten is a protein found in grains such as wheat, rye, spelt, malt and barley. In a sensitive person, gluten damages the lining of the small intestine and interferes with nutrient absorption. This damage can go undetected for some time. Typical symptoms of celiac disease are abdominal pain, diarrhea, irritability, poor weight gain, and slow growth. Celiac disease may reveal itself shortly after the infant has his first bowl of cereal, but in some cases, symptoms are so minor that the condition can smolder at a low level for years and a diagnosis may not be made until adolescence or even adulthood.