What is a food allergy?
If your child has a food allergy, it means their body’s immune system reacts to certain foods. Even though the food may be safe to eat, their body wrongly sees some proteins in the food as something harmful. This can lead to unpleasant side-effects that can be difficult to live with.
What causes food allergies in children?
Although food allergies in children are becoming increasingly common, it’s not completely clear why this is the case. One theory is that children aren’t as exposed to bugs as they were in the past, and so their immune system doesn’t get the chance to develop as well. Another is that our bodies aren’t used to the processed foods in a Western diet.
But your child may be more likely to develop a food allergy if:
- they already have another food allergy
- they have atopic eczema (a condition that causes itchy, red skin)
- there’s a family history of food allergies or other allergic diseases (such as hay fever, asthma or eczema)
What are the symptoms of a food allergy?
How one child’s body reacts to a food allergy may be different to another’s. Some symptoms will be more severe than others, but there are some classic signs of food allergies to keep a close eye out for. They usually affect the skin, the respiratory system (lungs and breathing) and/or the digestive system and can include:
- a skin reaction, for example hives (itchy bumps on your skin), a rash or flushed (red) skin
- a runny, blocked or itchy nose or sneezing
- sore, red, swollen, itchy or watery eyes
- itchy or swollen lips, mouth, tongue or throat
- finding it harder to breathe or talk
- constipation, diarrhoea, tummy cramps, feeling sick or being sick
- wheezing, a cough, noisy breathing, or shortness of breath
- feeling bloated (a swollen tummy)
Sometimes, a life-threatening allergic reaction may occur. This is known as anaphylaxis (a-na-fa-lac-sis). If at any point your child has a severe reaction – such as finding it hard to breathe, a tight chest, wheezing, their mouth or lips begin to swell, they feel dizzy or lose consciousness – you should call 999 immediately.
What are the most common food allergies in children?
The most common food allergies in children include:
- cow’s milk
- hen’s eggs
- tree nuts, for example almonds, walnuts, cashews, pistachio nuts, pecans, hazelnuts and Brazil nuts
- shellfish, for example prawns, crab and lobster
- seeds, for example sesame seeds
What’s the difference between a food allergy and a food intolerance?
A food allergy is when your child’s immune system mistakes a protein within a food as something harmful. This can lead to the following reactions.
- The first is when your immune system produces an antibody in response to the protein. An antibody (sometimes called an immunoglobulin) is a protein your immune system makes when it detects and tries to fight something harmful, such as bacteria or a virus. The antibody your immune system produces that causes an allergic reaction to food is called an ‘IgE antibody’. This usually happens very quickly (within 20 minutes to 2 hours) and is known as an ‘IgE-mediated food allergy’.
- The second is a delayed food allergy. In this case, your immune system is still involved, but it doesn’t make an antibody. Symptoms tend to come on more slowly, sometimes up to several hours or even days later. This is also known as a ‘non-IgE-mediated food allergy’. It’s also possible to have symptoms from both of these types of reaction.
A food intolerance is not caused by your immune system. There are lots of different things that can cause a food intolerance. For example, your digestive system might be sensitive to an additive or chemical found in food, or lack certain enzymes needed to break down food. Symptoms might be mild or severe and can come on quickly or slowly. This can make it much harder to decide whether symptoms are caused by a particular food or by something else, such as stress or anxiety.
How do I know if my child has a food allergy?
If your child has a reaction and you suspect it’s a food allergy, speak to your GP. They will ask you some questions about your child’s symptoms and medical history and may refer your child to a specialist for tests. Depending on your child’s symptoms and the type of food allergy that’s suspected, these might include:
- a blood test to test for the IgE antibody that triggers an allergic reaction
- a skin-prick test, where small amounts of the suspected allergen are placed on to your child’s skin. Their skin is then pricked with a needle and any reaction is monitored for the next 15 to 20 minutes. This should only be done where there are facilities to deal with an anaphylactic reaction.
- an oral food challenge, where small amounts of the suspected allergen are given to your child, starting on their lips. This gradually increases before moving on to them eating small amounts and monitoring their reaction.
- a trial elimination diet, where the suspected food is removed from your child’s diet for two to six weeks before being reintroduced. Their symptoms will be monitored throughout.
It’s important that these tests are done under the supervision of a trained medical professional.
There are lots of different food allergy tests available from commercial companies, but these aren’t always reliable or evidence-based.
You also shouldn’t remove complete food groups from a child’s diet without supervision from a registered paediatric dietitian. It’s important to seek help from a registered health professional to help diagnose a food allergy.
How do you treat food allergies in children?
The treatment your child will need for their food allergy will depend on how severe their symptoms are. For allergic reactions like hives or itchy skin, speak to your doctor or pharmacist. They might recommend antihistamines or be able to give you further advice. But for severe cases such as an anaphylactic reaction, they may need to carry adrenaline (such as an EpiPen) with them at all times.
The best way to treat a food allergy is to completely avoid eating the food that’s causing the reaction. The only exception could be if a healthcare professional advises otherwise, for example if they suggest gradually reintroducing a certain food to your child’s diet.
Cutting a food out completely isn’t always easy as you learn to navigate food labelling and restaurant menus. But as a parent, the most important thing you can do is to educate yourself as much as possible, be vigilant and understand what to do in an emergency.
You might find it helpful to have an emergency plan put together by your doctor that you can share with teachers and family members. You could also ask your child to wear a medical emergency identification (ID) bracelet. Speak to a specialist dietitian for more advice. You can also access support groups for helpful tips.
Will my child grow out of their food allergy?
Some food allergies can go away by the time your child starts school. This can partly depend on what food is causing the allergy. It’s possible your child could grow out of an allergy to cow’s milk, wheat, soya or eggs. Other food allergies, such as peanuts, tree nuts, fish or shellfish, are more likely to continue into adulthood, so your child may not outgrow them.
Even if your child may have outgrown an allergy, you should follow the advice of a healthcare professional, such as a qualified dietitian, before reintroducing trigger foods.