Food allergies in children – symptoms, examination and treatment

Food allergy in children is an immunological reaction in which the body's immune system produces antibodies (IgE) against proteins in certain foods. The condition is most common in the first three years of life, with an estimated overall incidence of around 7-8 percent. 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 within a short time after the child has consumed the food they are reacting to – often within minutes to an hour. The most common reactions are seen on the skin in the form of a rash, hives or worsening of eczema.

Other common symptoms include itching and swelling around the mouth, vomiting, stomach pain or diarrhoea. Some children also experience respiratory symptoms, such as coughing or chest tightness. Most reactions are mild and go away on their own if the child does not continue to eat the food they are reacting to.

In rare cases, a food allergy can trigger a severe, acute reaction (anaphylaxis) that affects multiple body systems at the same time. Signs of this may include swelling of the throat or tongue, difficulty breathing, or a sudden drop in blood pressure. Such a reaction requires emergency medical attention.

What is the most common food allergy in infants?

Cow's milk allergy is the most common food allergy in infants. About 2-3 percent 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 greatly from child to child and can manifest as a rash, stomach symptoms such as vomiting or loose stools, or as a worsening of eczema. In breastfed infants, symptoms of cow's milk allergy can rarely occur via cow's milk protein in the mother's diet.

The good news is that most children outgrow their cow's milk allergy during the first few years of life. Around 90 percent can tolerate milk again by the age of 3, and half can tolerate it even earlier.

What is the difference between food allergy and food intolerance?

Food allergies and food intolerances often cause similar symptoms, but are caused by different mechanisms in the body. In a food allergy, the immune system reacts by forming antibodies against proteins in the food, while food intolerances are typically caused by the body having difficulty metabolizing or digesting a particular food – without the immune system being involved.

The symptoms of intolerance usually appear later and are often milder than those of allergy, and more of the food must typically be consumed before symptoms appear. An example of intolerance is lactose intolerance, where the body has a reduced ability to break down milk sugar. However, it can be difficult to determine whether it is an allergy or intolerance based on symptoms alone, which is why a medical assessment is important.

How are food allergies tested in children?

The assessment always starts with a thorough conversation about the child's symptoms, when they occur, and which foods are involved. This conversation is crucial for which tests are subsequently relevant.

Skin prick tests and blood tests that measure specific IgE antibodies can be used to investigate whether there is allergic sensitization to certain foods. However, these tests cannot stand alone – a positive result shows that the child is sensitized, but not necessarily that the child will experience symptoms when eating the food.

How are food allergies treated in children?

The main treatment for food allergies is to avoid the food the child is reacting to. It is therefore important to get a correct diagnosis so that the child's diet is not unnecessarily restricted based on an assumption that is not valid.

For children at risk of severe reactions, the doctor may prescribe an adrenaline pen (auto-injector), which parents and other caregivers, e.g. in daycare or school, should be instructed to use. Antihistamines can be used in some cases to reduce mild symptoms such as itching, but are not a substitute for avoiding the triggering food.

Since many children eventually develop tolerance to foods they previously reacted to – especially milk and eggs – the doctor will typically make a plan for when and how to assess whether the child can tolerate the food again. This often happens through a new, controlled provocation and should always be done in consultation with a doctor.

Can my child grow out of a food allergy?

Yes, it is common, especially for allergies to milk and eggs, where many children develop tolerance during childhood. Allergies to foods such as peanuts, tree nuts and shellfish, on the other hand, are more often more persistent.

It is important that any reassessment of whether the child can tolerate the food again is done by a doctor and not tested at home on your own, as the reaction upon renewed contact may be different than before.

When should you see a doctor about your child's food allergy?

Contact your doctor if your child has repeated reactions to certain foods, such as rashes, vomiting or stomach pain shortly after meals. The same applies if a child with a known allergy or eczema does not respond as expected to treatment.

Seek emergency help (112) if the child develops swelling in the throat, tongue or lips, has difficulty breathing, becomes limp or seems very ill shortly after eating - this may be a sign of a serious allergic reaction.

Treatment at Charlottenlund Private Hospital

At Charlottenlund Private Hospital, you can get a thorough assessment of your child's symptoms from a specialist. We will review your child's medical history and symptom pattern with you, and make a plan for which tests are relevant, as well as how to best handle any food allergies in everyday life.

Book an appointment online if you want a specialist assessment of your child's symptoms.

Experience and skills at Charlottenlund Private Hospital

At Charlottenlund Private Hospital, children with suspected food allergies are evaluated by pediatric specialists. The evaluation is based on the child's medical history supplemented with skin prick tests and specific IgE blood tests after individual assessment, and a confirmed diagnosis often requires a controlled provocation. You will find an overview of all departments on our department page.

Sources:

- Danish Paediatric Society: Allergy assessment of children and adolescents – nationwide clinical guideline.