Food allergies in children – symptoms, examination and treatment
Food allergies in children are immune reactions in which the body's immune system produces antibodies (IgE) against proteins found in certain foods. The condition is most common during the first three years of life, with an estimated prevalence of approximately 6–8%, according to the Danish Paediatric Society. The most common triggers in young children are cow's milk and eggs, and many children outgrow these allergies during childhood.
Food allergies in children are immune reactions in which the body's immune system produces antibodies (IgE) against proteins found in certain foods. The condition is most common during the first three years of life, with an estimated prevalence of approximately 7–8%. The most common triggers in young children are cow's milk and eggs, and many children outgrow these allergies during childhood.
What Are the Symptoms of Food Allergies in Children?
Symptoms typically appear shortly after a child consumes the food they are allergic to, often within minutes to an hour. The most common reactions affect the skin and include rashes, hives or worsening eczema.
Other common symptoms include itching and swelling around the mouth, vomiting, abdominal pain or diarrhoea. Some children may also experience respiratory symptoms, such as coughing or chest tightness. Most reactions are mild and resolve on their own if the child does not continue eating the food that triggers the reaction.
In rare cases, a food allergy can cause a severe, acute reaction (anaphylaxis), in which several of the body's organ systems are affected simultaneously. Signs may include swelling of the throat or tongue, difficulty breathing or a sudden drop in blood pressure. Such a reaction requires immediate medical attention.
What Is the Most Common Food Allergy in Infants?
Cow's milk allergy is the most common food allergy in infants. Approximately 2–3% of all children develop cow's milk allergy, and almost all cases occur during the first year of life.
The symptoms of cow's milk allergy vary considerably from child to child and may include skin rashes, gastrointestinal symptoms such as vomiting or loose stools, or worsening eczema. In breastfed infants, symptoms of cow's milk allergy may occasionally develop due to cow's milk proteins passing through the mother's diet.
The good news is that most children outgrow cow's milk allergy during their early years. Approximately 90% can tolerate milk again by the age of three, and half develop tolerance even earlier.
What Is the Difference Between Food Allergy and Food Intolerance?
Food allergies and food intolerances often cause similar symptoms, but they involve different mechanisms in the body.
In a food allergy, the immune system reacts by producing antibodies against proteins in food. Food intolerance, on the other hand, typically occurs when the body has difficulty processing or digesting a particular food, without the immune system being involved.
Symptoms of food intolerance usually develop later and are often milder than allergic reactions. A larger amount of the food generally needs to be consumed before symptoms appear.
An example is lactose intolerance, in which the body has a reduced ability to break down milk sugar (lactose).
However, it can be difficult to determine whether symptoms are caused by an allergy or an intolerance based on symptoms alone, which is why a medical assessment is important.
How Are Food Allergies Diagnosed in Children?
The diagnostic process always begins with a thorough discussion of the child's symptoms, when they occur and which foods may be involved. This discussion is essential in determining which tests are appropriate.
Skin prick tests and blood tests measuring specific IgE antibodies can be used to investigate whether a child has developed allergic sensitisation to certain foods.
However, these tests cannot be used on their own to establish a diagnosis. A positive result indicates that the child is sensitised to a particular food, but it does not necessarily mean that eating the food will cause symptoms.
How Are Food Allergies Treated in Children?
The main treatment for food allergies is avoiding the food that triggers the child's allergic reaction. It is therefore important to establish an accurate diagnosis so that the child's diet is not unnecessarily restricted based on an incorrect assumption.
For children at risk of severe allergic reactions, the doctor may prescribe an adrenaline auto-injector. Parents and other caregivers, such as nursery or school staff, should be instructed in how to use it.
Antihistamines may sometimes be used to relieve mild symptoms such as itching, but they do not replace avoiding the food responsible for the reaction.
As many children gradually develop tolerance to foods they previously reacted to — particularly milk and eggs — the doctor will usually develop a plan for when and how to assess whether the child can tolerate the food again.
This often involves a repeat, medically supervised oral food challenge and should always be carried out in consultation with a doctor.
Can My Child Outgrow a Food Allergy?
Yes. This is common, particularly with milk and egg allergies, as many children develop tolerance during childhood.
Allergies to foods such as peanuts, tree nuts and shellfish, however, are more likely to persist.
It is important that any reassessment of whether the child can tolerate the food again is carried out by a doctor rather than being attempted at home without medical supervision, as the reaction upon re-exposure may be different from previous reactions.
When Should You Seek Medical Advice for Your Child's Food Allergy?
Contact a doctor if your child experiences repeated reactions to specific foods, such as rashes, vomiting or abdominal pain shortly after meals.
The same applies if a child with a known allergy or eczema does not respond to treatment as expected.
Seek emergency medical assistance (112) if your child develops swelling of the throat, tongue or lips, experiences difficulty breathing, becomes limp or appears severely unwell shortly after eating. These may be signs of a serious allergic reaction.
Treatment at Charlottenlund Privathospital
At Charlottenlund Privathospital, your child can receive a thorough assessment of their symptoms by a medical specialist.
We review your child's medical history and symptom patterns together with you and develop a plan for which examinations are appropriate and how any confirmed food allergy can best be managed in everyday life.
Book an appointment online if you would like your child's symptoms to be assessed by a specialist.
Experience and Expertise at Charlottenlund Privathospital
At Charlottenlund Privathospital, children with suspected food allergies are assessed by specialists in paediatrics.
The diagnostic process is based on the child's medical history, supplemented by skin prick tests and specific IgE blood tests where appropriate following an individual assessment. A confirmed diagnosis often requires a medically supervised oral food challenge.
You can find an overview of all departments on our departments page.
Sources:
- Danish Paediatric Society: Allergy Assessment in Children and Adolescents – National Clinical Guideline
Frequently Asked Questions
What are the most common symptoms of food allergies in children?
The most common symptoms are rash, hives, itching around the mouth, vomiting and stomach pain. The symptoms typically appear shortly after the child has eaten the triggering food.
Which foods most often cause allergies in children?
The most common triggers in young children are cow's milk and eggs. Other foods that often cause allergies are peanuts, tree nuts, fish and shellfish.
How are food allergies tested in children?
The assessment starts with a conversation about symptoms and diet. This may then include skin prick tests and blood tests, and in some cases a controlled food challenge, where the child is gradually given the suspected food under observation.
Do children grow out of food allergies?
Yes, allergies to milk and eggs in particular often outgrow themselves during childhood. Around 90 percent of children with cow's milk allergy can tolerate milk again by the age of 3. Allergies to nuts and shellfish are often more persistent.
What is the difference between food allergy and food intolerance?
In case of food allergy, the immune system reacts with antibodies against proteins in the food. In case of intolerance, the body has difficulty digesting the food, and the symptoms often appear later and are milder.
Can a blood test or skin prick test alone determine whether my child has a food allergy?
No, a positive test shows that the child is sensitized, but not necessarily that they will experience symptoms from the food. The result should always be seen in the context of the child's symptoms, and in some cases a provocation test is necessary to make the diagnosis.
What to do if my child has a severe allergic reaction?
If there are signs of a serious reaction, such as swelling of the throat, difficulty breathing or lethargy, seek emergency help by calling 112. Children at risk of such reactions may have an adrenaline pen prescribed by their doctor.
Should my child follow a strict diet if a food allergy is suspected?
Dietary changes should be made in consultation with a doctor so that the child's diet is not unnecessarily restricted if the allergy has not been confirmed. It is important to get a correct diagnosis first.
Can food allergies be linked to eczema in children?
Yes, children with eczema (atopic dermatitis) have an increased risk of also having food allergies, and in some of these children, a food can be a contributing factor in worsening the eczema.
When should you see a doctor about your child's food reactions?
Contact a doctor if your child has repeated reactions to certain foods, such as a rash or stomach symptoms. Seek emergency help if there are signs of a serious reaction, such as swelling of the throat or difficulty breathing.