Food allergy is a potential health threat affecting young children. The body’s immune system keeps your child healthy by fighting against infections and safeguard health. A food allergy occurs when your child’s immune system overreacts to a food or a substance in a food – the allergen, identifying it as a danger and triggering a protective response. ‘Food hypersensitivity’ is a collective term to describe any adverse reaction occurring in your child’s body in response to a food. When food allergy is unrecognized in a child it leads to impaired quality of life, less social interactions and other health related comorbidities.
Types of allergies
The major types of allergic reactions are: (1) Toxic food reactions: in response to substance(s) that contaminate foods or that are naturally present in them, e.g., toxins in non-edible mushrooms. (2) Non-toxic food reactions: an individual's susceptibility to certain foodstuffs. It is further divided into immune-mediated (IgE) and non-immune mediated (non-IgE) reactions. Food allergy is the term commonly used for immune-mediated reactions, while food intolerance includes all non-immune mediated reactions.
Major food allergens
The Food Allergy Labelling and Consumer Protection Act (FALCPA) passed in 2004 by the Food and Drug Administration (FDA) listed eight major food allergens. The act requires the labelling (on the package) of any food containing a major allergen, defined by the FALCPA as a protein from one of the eight foods, which account for 90 per cent of all food allergies:
3. Cow’s milk
6. Crustacean Shellfish
7. Tree nuts and
Symptoms of food allergy in toddlers
When a child who is allergic to a food substance happens to feed on it, the allergen gets absorbed into the bloodstream and causes skin reactions such as rashes, hives or eczema. In severe cases it may also block the air passage and cause asthmatic symptoms such as light-headedness and weakness leading to anaphylaxis. Anaphylaxis is a condition in which two or more of the following symptoms occur rapidly and acutely – involvement of the skin, respiratory or cardiovascular symptoms, persistent gastrointestinal symptoms; and hypotension (a sudden drop in the blood pressure). Anaphylactic reactions can be fatal if not treated quickly. Other kinds of reactions to foods that are not food allergies include food intolerance (such as lactose or milk intolerance, gluten or wheat intolerance), food poisoning and toxic reactions. Food intolerance is triggered by mechanisms distinct from the immunological reaction responsible for food allergy.
Diagnosis of food allergy has to be based on:
i. Clinical history
To identify and define the cause-effect relationship between the allergen and the reaction in the child.
ii. Elimination diets
The purpose of an elimination diet is to discover the symptom-triggering foods in your child. Eliminating the foods you think may be the source of your child’s symptoms is the key concept of elimination diet. In order to confirm an allergen, remove those foods that most commonly provoke a reaction in your child, for two-weeks. In addition to the suspected foods, make sure you avoid alcoholic beverages, caffeinated drinks (coffee, tea and colas), Monosodium glutamate (MSG), aspartame, nitrates (chemical stabilizers in frozen meats) and sulfites (preservatives used in jams and dried fruits) to avoid cross reactivity. After 2 weeks on the elimination diet, it is time to start testing foods. Add one food at a time, every 3 days and observe your child’s response to each suspected food. The suspected food which triggers symptoms in your child alone should be eliminated from his/her diet. The problem with using an elimination diet is its potential for nutritional deficiencies.
iii. The oral food challenge
Standardised oral challenge (ideally performed double blind and placebo controlled) remains the gold standard in diagnosing food allergy. The open challenge is the easiest to perform on a trial basis, in which the patient is made to eat a small quantity of the suspected food in its natural form, under careful medical supervision and monitored for its response.
iv. Skin prick test
This is a simple but effective test and carried out by trained staff. With the wide range of standardised allergen extracts available, this facilitates testing different extracts at the same time. A drop of an allergen extract is placed on the skin and the acute response is monitored and noted.
v. Diet diary
Food hypersensitivity can also be monitored by maintaining a diet diary. Record everything your child eats everyday along with any reactions encountered. By the end of a month, you should be able to identify and understand your child’s responses to suspected foods.
The timing of introducing complementary foods to your baby by prolonging exclusive breastfeeding until six months is a method of allergy prevention. Maintaining a record for your child on symptom-safe list of foods and preparing a menu plan in consultation with an experienced dietitian would do wonders in preventing nutritional deficiencies and co-morbidities. The more whole, unprocessed foods your child eats the better it is in preventing the episodes of allergic reactions. When it comes to packaged foods, make sure you read the ‘Allergen advice’ and ‘List of ingredients’ mentioned on the label and make informed dietary choices. Ensuring proper food safety practices at home and being cautious while eating out are effective measures to tackle food hypersensitivity in children.