Causes Of Food Allergies In Children, Symptoms And Treatment

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Food allergies in children are not uncommon. According to the American College of Allergy, Asthma & Immunology (ACAAI), food allergies may affect about four to six percent of all children (1). Most food allergies appear early in childhood. Therefore, parents should stay informed about potential food allergens for children.

A food allergy is an abnormal immune system response to a food protein when it is mistaken to be a pathogen. The immune system attacks the protein, causing mild to moderate symptoms, such as wheezing, skin rash, and abdominal cramps. In rare cases, the symptoms might progress to a more severe and life-threatening condition called anaphylaxis.

Read this post to know about the causes, symptoms, diagnosis, treatment, and prevention of food allergies in children.

Is Food Allergy And Food Intolerance The Same?

Although food allergy and food intolerance manifest similar symptoms, they are different conditions. Food allergy is an immune system-related condition characterized by an allergic reaction to a food. On the other hand, food intolerance is a digestive disorder characterized by the inability to digest certain foods (2).

Food allergy affects numerous organs in the body and causes mild or moderate to severe symptoms, such as anaphylaxis. In contrast, food intolerance primarily causes gastrointestinal symptoms, and the symptoms are seldom severe (3).

Causes Of Food Allergy

The exact cause of food allergy is not known. However, experts believe that a food allergy develops due to a combination of genetic and environmental factors.

In an episode of food allergy, the body perceives a food protein as an antigen, a potential danger. The body produces specialized proteins called immunoglobulin (IgE) antibodies to fight off the threat. Upon release, these antibodies signal the body to release histamine and other chemicals.

The chemicals can trigger symptoms, such as skin rash or hives, wheezing, nasal congestion, abdominal pain, vomiting, and diarrhea (4) (5).

When a child gets a food allergy, they must have been exposed to the food at least once, or they could have been sensitized through breast milk before developing an actual allergic reaction. It means that when a child gets an allergic reaction, it is the second time that the child has contacted the allergen (4).

Foods That Might Trigger Allergy In Children

Although almost any food can trigger an allergic reaction, the following eight foods account for approximately 90% of food allergies (6).

  • Milk
  • Eggs
  • Peanuts
  • Soy
  • Fish, such as salmon, cod, and tuna
  • Shellfish, such as lobster and shrimp
  • Wheat
  • Tree nuts, such as almonds, walnuts, pecans, and cashews

Besides these, sesame and mustard seeds are also considered major food allergens in some countries.

Symptoms Of Food Allergy

Allergic reactions to food can cause a range of symptoms, and the severity of these symptoms may vary from one child to another.
The following are the common mild to moderate symptoms of a food allergy in children (1) (4) (5) (6).

  • Red spots on the skin (hives)
  • Itchy skin rashes (eczema or atopic dermatitis)
  • Runny or stuffy nose
  • Swelling of the mouth, tongue, or throat
  • Sneezing or wheezing
  • Abdominal cramps or stomach pain
  • Nausea or vomiting
  • Diarrhea

In some cases, anaphylaxis may also occur. Anaphylaxis is a severe and life-threatening reaction that requires immediate medical intervention. The symptoms of a severe allergic reaction include

  • Pale or blue-colored skin.
  • Swollen neck and itchiness and tightness of the throat.
  • Shortness of breath and difficulty breathing.
  • Dizziness, with low blood pressure.
  • Partial or complete loss of consciousness.
  • Seizures.

Most food allergy reactions occur within minutes to an hour or two after ingesting a food. In some rare cases, this can occur after four to six hours or even longer.

Note: A reaction after ingesting food isn’t always a food allergy. In some cases, a child may experience an allergic reaction after eating raw or undercooked fruit or vegetables. This condition is called oral allergy syndrome, wherein the body reacts to pollen in the food and not the food itself (1).

Diagnosis Of Food Allergy

A doctor will study the child’s symptoms and note their dietary, family, and medical history. Based on the suggestive findings, they may conduct the following tests (1) (5).

1. Physical examination: The doctor will examine the child’s skin and look for signs of rashes. They will also evaluate the child’s vital parameters, such as heart rate and blood pressure. Additionally, the doctor may ask specific questions to the child or their parents, such as

  • “What did the child eat, and how much?”
  • “How long did it take for the symptoms to develop?”
  • What specific symptoms did they have and how long did they last?”

2. Elimination test: This simple test involves eliminating the specific food from the diet and then reintroducing it to check if the reintroduction triggers a reaction. If the pediatrician suspects a food allergy, they will refer you to an allergist for further investigation.

3. Blood test: A blood test helps determine whether the child has food-specific IgE antibodies in the body. If the antibodies are present, the test measures the amount of antibodies present in the blood. The doctor correlates the test results with the information collected during the physical examination.

4. Skin-prick test: This test is the most accurate way to ascertain the cause of food allergies. The test involves placing a small, diluted quantity of suspected allergen on the back of the child’s hand or forearm. The doctor then pricks the skin using a small, sterile probe, which allows the diluted allergen to enter the skin. In a positive test, the child develops a raised, reddish bump on the pricking site within 15 to 20 minutes. This doctor will not perform this test if the child recently had a severe reaction or has chronic eczema or hives.

If the skin or blood tests are inconclusive, the allergist may recommend an oral food challenge test. This test helps determine if the child has outgrown a food allergy.

5. Oral food challenge test: In the test, the child is made to eat a tiny amount of the suspected food under supervision. If there’s no reaction, the amount of food is increased until the child eats a serving of the food. If the child develops a reaction, it indicates a positive case of allergy for the suspected food. This test is done in an allergist’s office with emergency medical arrangements due to its potential of triggering severe allergic reactions.

Treatment For Food Allergy

There’s no single medication to treat food allergies in children. If a child is diagnosed with a food allergy, the following interventions may help treat the symptoms (1) (4) (5).

1. Remove the allergenic food from the diet

Remove the allergenic food and other foods that contain the allergen from the child’s diet. For instance, if your child has a milk allergy, they should avoid milk and milk products. Consult a pediatric nutritionist to devise a well-balanced diet plan and replace the allergenic food with its healthy alternatives.

2. Use oral supplements whenever necessary

Your doctor and pediatric nutritionist can help you determine whether your child needs a supplement. In some cases, where the child has an allergy to multiple foods, such as milk and soy, they may require nutritional supplements to support their dietary requirements.

3. Use oral antihistamines

This can help relieve allergy symptoms, such as swelling, runny nose, or abdominal pain. Consult the pediatrician for the correct dosage. The doctor may also prescribe an epinephrine auto-injector to tackle a severe allergic reaction. Parents should train their child to use the auto-injector and inform the concerned authorities, such as school teachers, about its use for the child.

Several allergies may last for a short time, and some may resolve when the child is three or four years old. Follow-up testing and periodic evaluation of the child’s condition will help determine if the child is still allergic to a particular food.

Prevention Of Food Allergy In Children

You could take the following measures to prevent allergy in children (1) (7).

1. Avoid feeding allergenic food to your child if they develop an allergy. It involves its derivatives and other foods that could contain the allergen or its derivatives. For instance, if your child has a peanut allergy, they must avoid peanuts and any food that is made from peanuts or contains peanuts. Certain energy bars, cakes, and muffins generally contain peanuts.

2. Read the ingredient list carefully while buying packaged food. It will help you know if the food contains a potential allergen. Children with food allergies should also learn to read the food label and ingredient list. It will help them stay cautious and responsible in food selection when you aren’t around.

3. Check the restaurant menu carefully and ask the concerned person about a dish and its ingredients while eating out with your child. It will help minimize the chances of an accidental allergic reaction. Alternatively, try to carry homemade food for the child whenever eating out. This way, you can ensure the child is eating safe food. Also, it saves you from the hassle of finding appropriate food for your child, which isn’t always easily available.

4. Encourage your child to always carry an epinephrine auto-injector with them. Train them to use the injector themselves. If your child goes to daycare, playschool, or school, inform the teachers about the child’s condition. Tell them about the food/foods they can or can’t eat. Also, guide them on how to use an auto-injector in case of an emergency.

5. Reintroduce a food after consulting your child’s healthcare provider. It applies to cases where you suspect that the child has outgrown the allergy. The doctor will perform specific tests to confirm your suspicions and guide you on how much quantity and how you can begin reintroducing the food to your child.

6. Get social and mental health support for your child and the family. Bringing up a child with food allergies can get overwhelming at times. In such times, talking to parents who have children with allergies can help resolve some anxieties. Also, you and your child can speak to a mental health professional who could educate you on ways to manage allergies and live a happy and productive life.

As your child grows and understands their condition better, they will manage it themselves with minimum support from you or people around them.

Food allergies in children occur when the immune system misinterprets food proteins as pathogens and attacks them. It may cause symptoms such as skin rashes, abdominal discomfort, or severe breathing issues in children. Eggs, peanuts, soy, wheat, tree nuts, and shellfish are common allergens. A food allergy is usually diagnosed by physical examinations, blood tests, and skin prick tests. When introducing children to a new food, offer it in small amounts. Further, feed them single-ingredient foods to identify that they are allergic to.

Key Pointers

  • Children may be allergic to soy, milk, nuts, and various other food items.
  • The symptoms are different for each child and may include rashes, diarrhea, swelling of the mouth, or stomach pain.
  • Follow the tips mentioned in this post to prevent allergic reactions in the future and consult a doctor if complications arise.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. Food Allergy;American College of Allergy, Asthma & Immunology
2. Food allergy, intolerance, or sensitivity: What’s the difference, and why does it matter?;Harvard Health Publishing
3. Food Allergy vs. Intolerance: Knowing the Difference;Nationwide Children’s
4. Food Allergies in Children;Johns Hopkins Medicine
5. Food Allergies in Children;University of Rochester Medical Center
6. Food Allergies in Children;AAP
7. Reducing the Risk of Food Allergies;Academy of Nutrition And Dietetics
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Dr. Dur Afshar Agha

Dr. Dur Afshar Agha is a consultant pediatrician with decades of experience in various medical facilities both in Pakistan and Saudi Arabia. She has headed the Department of Preventive Pediatrics at the prestigious, Children’s Hospital and Institute of Child Health in Pakistan and is a life member of the Pakistan Paediatric Association. She has also completed her Post Graduate Program... more

Swati Patwal

Swati Patwal is a clinical nutritionist and toddler mom with over eight years of experience in diverse fields of nutrition. She started her career as a CSR project coordinator for a healthy eating and active lifestyle project catering to school children. Then she worked as a nutrition faculty and clinical nutrition coach in different organizations. Her interest in scientific writing... more