Food Allergies in Children
As parents, we do our best to provide our children with the best nutrition with a wide range of foods for variety and balance. However, there are times when kids develop reactions after eating certain types of food – a result of food allergies or intolerances.
A food allergy is an abnormal response of the body’s immune system to food. The immune system normally works to protect us against harmful microbes. If the immune system is triggered by food, a food allergy develops.
There are some common foods that may trigger an allergic reaction in children. These include common ingredients such as eggs, milk, peanuts, tree nuts like almonds and cashews, soy and wheat. Genetic predisposition is the most common reason why some children develop a food allergy. If either parent or both parents have food allergies, respiratory allergies or eczema, then the child has an increased risk for developing a similar allergic condition. Children with eczema also have a higher risk of developing food allergies.
What are the symptoms of a food allergy?
The most common symptoms of food allergy are skin symptoms. Within minutes to a few hours after eating the food, the child can develop hives – red itchy, raised rashes that vary in size, in any part of the body. Some children can also develop a swell in the lip or the area around the eye.
The second most common symptoms are gastrointestinal symptoms, which include stomach pain, vomiting or diarrhoea.
Food allergies may also cause more severe symptoms such as breathing difficulties, swelling in the throat, swelling of the tongue, or even a reduction in blood pressure which may cause a child to look pale or feel faint.
What is a food intolerance?
Food intolerance is unacceptance of food by the body due to physiologic reasons. The most common type of food intolerance is lactose intolerance. This is because the body lacks the enzyme lactase, which helps to break down lactose, the main carbohydrate in dairy products such as fresh milk and cheese. People with lactose intolerance may develop abdominal pain, bloating, or diarrhoea after consuming dairy.
Food intolerance can also be caused by reactions to naturally occurring chemicals in food. A common example is developing insomnia, restlessness or jitters after taking coffee or other caffeinated drinks. Others may react to food additives such as monosodium glutamate (MSG). They may experience headaches, hot flushes and even chest pain after consuming food containing MSG.
How do you differentiate between a food allergy and food intolerance?
A food allergy is more commonly seen among infants and young children while food intolerances develop usually towards adolescence and even adulthood.
Children with food allergy can develop symptoms even when exposed to just a small amount of the culprit food. In contrast, the symptoms of food intolerance are dose-related. People with food intolerances are more likely to develop symptoms if they consume a large amount of the food or if they eat the food frequently.
Food allergies can result in severe, life-threatening symptoms. Anaphylaxis is a serious allergic reaction that can cause breathing difficulties, loss of consciousness, and reduction in blood pressure. Without proper treatment, it can be fatal. Anaphylaxis does not occur in food intolerance.
How is food allergy diagnosed?
When you bring your child for a consult, the doctor will ask detailed questions about your child’s medical history, such as the types of food(s) that trigger a reaction, what symptoms develop, and how long it takes for the symptoms to develop after exposure to the (offending) food.
Depending on your child’s medical history, an allergist can perform or request for any of the following tests to confirm the diagnosis of food allergy:
- Skin prick tests
- IgE (immunoglobulin E) bloods tests (to test for allergen antibodies formed in the presence of allergies)
- Oral food challenge
What is a skin prick test?
A skin prick test is used to identify allergy-causing substances or allergens. In this test, the allergens are inserted into the skin layers and observed for allergic reactions.
When an allergen is inserted into the skin, the body treats it like a foreign substance and produces antibodies to fight against it. The binding of the allergen to the antibody release chemicals such as histamine that triggers an allergic reaction.
How is a skin prick test conducted?
Before conducting the skin prick test, your doctor will review your child’s medical history and perform a physical exam.
A small drop of the suspected allergen is placed on the skin on the child’s back or forearm. Next, the top surface of the skin is scratched lightly with a small needle. The skin is then observed for signs of allergic reactions.
The results are obtained within 15 minutes. If your child is allergic to one of the substances tested, they will develop a red, swollen, and itchy bump at the prick site.
How can you prepare for the test?
Medications can interfere with results; hence your child should not be taking any antihistamine medications or cough mixtures for 5 days before the test.
Is the test safe for children?
The skin prick test is safe and painless. Some may find it slightly irritating. The skin reaction subsides on its own within a couple of hours. For children who experience discomfort from the itch, oral antihistamine or mild topical steroid cream may be prescribed.
With a skin prick test, different allergens can be identified in one go. Information from skin prick tests may help your child’s doctor develop an allergy treatment plan.
How is food allergy treated?
The main treatment for food allergy is to avoid the food that triggers the allergic reaction. It is important to read the ingredient labels on food products. Food products that contain the culprit food, even if it is only in small amounts, should not be given to your child. When eating out at restaurants, notify your servers about your child’s allergy. Inform them that even the pots, pans and utensils used to prepare your child’s food should not be contaminated with the culprit food.
It is also important to inform key people such as child care providers, school personnel, and the parents of your child’s friends, about your child’s food allergy. Explain to them how to recognise the symptoms of an allergic reaction, and what to do if your child has an allergic reaction. A written action plan describing how to care for your child is useful.
When should I see a doctor?
It is best to consult a doctor if you suspect that your child has a food allergy. If your child develops severe allergic reactions such as breathing difficulties, appears pale, or loses consciousness, do not delay going to the nearest Accident & Emergency (A&E) department.
Article reviewed by Dr Mohana Rajakulendran, paediatrician at Parkway East Hospital
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