Even everyday foods could trigger allergies. Find out if your children are susceptible

Your baby just had her first bites of peaches and hours later she’s sneezing and her nose is running. Could it be a food allergy?

Possibly. Symptoms of food allergies like diarrhoea, vomiting, skin rashes, runny noses and sneezing also resemble common childhood ailments, and a true diagnosis can only be made by a doctor. If you suspect a food allergy, keep a diary for several days of what your child eats and drinks and how she reacts, then consult your paediatrician. All too often parents assume symptoms like these are caused by a food allergy and needlessly eliminate nutritious foods from their children’s diets. This is not only a disadvantage to your child, but you may be misreading the first signs of an underlying illness when you pass off a problem as food allergy.

Much of the confusion over food allergy lies in its definition. In a true food allergy the allergen (the offending food, usually a protein) triggers an immune system response, producing antibodies called immunoglobulin E. These in turn cause the release of histamines responsible for multiple symptoms of an allergic reaction, which can range from minor sneezes and sniffles to anaphylaxis, a life-threatening condition.

The protein in cow’s milk, egg, peanut, fish, wheat, and soy are the most common food allergens, although any food may cause an allergic reaction. An allergy to a particular food may indicate an allergy to an entire food family, which is called cross-reactivity. For example, an allergy to peanuts may mean an allergy to the legume family (kidney beans, black-eyed peas and soy beans).

Fortunately, most children do not suffer from cross-reactivity and tend to be allergic to only one or two foods. If you discover that your child suffers from multiple food allergies, you should talk to a paediatric dietician who can help create a diet that eliminates the offending foods without sacrificing nutrients.

Babies are most susceptible to food allergies. They will outgrow most of these by age three, as the immune system becomes more mature. In fact, 70–80% of infants with a milk allergy will be able to tolerate milk by age four.

Food allergies to peanuts, fish and nuts tend to be an exception to the rule and often last a lifetime. For babies with a family history of allergies, the mum may want to nurse the baby for four to six months and eliminate the most potent allergens (milk, egg, fish, nuts) from her diet. This may help delay the onset and reduce the severity of food allergies. Wait until at least six months to offer dairy products or egg yolk to your child. At eight months introduce wheat, citrus fruits and cooked tomatoes. Fish, shellfish, peanuts, corn, berries, raw tomatoes and chocolate should be given to your child at ten months or later. Wait even longer to give your child foods that other family members are allergic to.

You can introduce solids to babies by trying one new food at a time, waiting three days or more between each new food. This will help identify which foods are okay and which may cause an allergic reaction.

The most common reactions to food allergies include vomiting, diarrhoea and abdominal cramping. Unfortunately these are also common indicators of food intolerances, which don’t involve the immune system, but occur for a variety of reasons, such as an enzyme deficiency (in lactose intolerance). Some natural acids in fruits may cause a rash around the mouth, and diarrhoea may be caused by excess sugar in fruit juice, which are both intolerances but non-allergic reactions. Food intolerances can also occur because the food contains a toxin, such as bacteria or poison. Another adverse reaction is chemical in origin and called a pharmacologic food reaction. An example of this is people who are ‘sensitive’ to caffeine and need only a single cup of coffee to get the jitters.

The most common allergic skin reaction to food is red, itchy hives that arise suddenly and disappear quickly. Another is a chronic itchy inflammation of the skin known as atopic dermatitis. An itchy, congested nose is a common respiratory tract allergic response. Eyes can react by becoming red, swollen and itchy. Persistent, chronic ear infections may also be an indicator of a food allergy. That’s because an allergy can cause congestion in the Eustachian tubes that connect the ears to the nose.

Once diagnosed, the only way to treat a food allergy is complete elimination of the food. Doing so for one to two years has been shown to result in the loss of the food allergy for about one third of people. Because children outgrow most food allergies, it’s a good idea to give your child new foods as she gets older.

Eliminating one food completely from your child’s diet can be a challenge, so be sure to read labels carefully. Also, be on the lookout for alternative foods that will substitute for missing nutrients. For a dairy-free diet, find other good sources of calcium, protein and vitamin D. For a wheat-free diet, look for foods rich in B vitamins.