Allergies in children: A simple guide for worried grown-ups

Allergies in children are a big deal, for them and for their family, and the number of kids affected is rising. Allergy symptoms can affect a child’s participation in regular activities, their safety (depending on the allergy) and their long-term health.^1,2  

Around 40% of children in the UK are affected by allergies.³ Allergies are unpredictable. The condition can improve, change or worsen with time.^1,2 If your child has an allergy, they are more likely to develop other allergies. They may also go on to have allergic asthma. So it’s important to get an early diagnosis of allergies in children and learn how to manage them.²

With an understanding of their allergy symptoms, an allergy management plan and the right treatment, many children with allergies lead normal, happy lives. And so do their mums and dads, brothers and sisters. Allergies don’t have to undermine your family’s quality of life. Read on to learn about why kids get allergies, whether it’s possible to prevent them starting and what the most common triggers are. 

What are allergies in children?

Allergies in children are hypersensitivity to a harmless substance like pollen, dust mites or food. The immune system is there to fight off threats like bacteria, parasites or viruses and it behaves in a similar way during an allergic reaction.⁴ That’s why allergy symptoms can resemble a childhood bug.⁵

Substances that trigger allergies are called allergens. On the first contact, the immune system creates Immunoglobulin E antibodies (IgE) to keep watch for that specific allergen in the future. Now your child is sensitised and could have an allergic reaction next time they encounter that same substance.⁴ This could be when allergies start to affect their daily life.

The impact on children of having allergies

Depending on the trigger, your child might not get to spend as much time outside at certain times of year or have the pet they want. Allergy can also impact their social life, mental wellbeing and concentration at school. Researchers even found having hay fever symptoms or taking hay fever medication made adolescents more likely to drop a grade from mock exams to GCSEs (Seasonal allergic rhinitis is associated with a detrimental effect on examination performance in United Kingdom teenagers: Case-control study, 2007).⁶ 

With food allergies, and others that carry a greater risk of life-threatening anaphylaxis, children may feel intense anxiety due to the need for constant vigilance.⁷

Why do kids get allergies?

The hygiene hypothesis suggests an overly clean environment in childhood could be responsible for kids getting allergies. This has evolved into the old friends hypothesis, that lack of exposure to harmless microorganisms (the old friends) stops the immune system from learning to react appropriately. Greater use of antibiotics has also been linked to the rise in allergies.^4,8 The debate continues.

Each year, new births add 43,000 cases of child allergy to the population in need of specialist care, according to Meeting the Challenges of the National Allergy Crisis: A report from the All Party Parliamentary Group for Allergy and the National Allergy Strategy Group (2021).³ Why one child gets allergies and not another isn’t fully understood. Recognised risk factors include family history and genes, as well as lifestyle and environmental factors.⁹

Family history and genes

A child is much more likely to develop allergies if their mum or dad also has allergies: ⁹

• The risk is 60-80% if both parents have allergies;
• 30-50% if one parent is affected;
• But 12% for a child in a family without allergies.

In some children the skin's natural barrier doesn't function as well as it should because of a faulty filaggrin gene. So allergens pass through more easily. Scientists have linked this to an increased risk of developing atopic dermatitis and allergies.²

Lifestyle and other factors

Environmental risk factors for developing allergies include: 

• Exposure to secondhand tobacco smoke, in the womb and afterwards ⁹
• Early feeding with formula milk and solid food ⁹
• Respiratory infections in young babies ⁹
• Living in urban or industrial areas, where air pollution is an indoor as well as outdoor issue ¹⁰

Can you stop allergies in children from starting?

Exposure to airborne allergens like plant pollen, pet dander or dust mites can sensitise your child, which is the first step to developing an allergy. ^4,9 But early exposure to animals may also be helpful according to Pet-keeping in Early Life Reduces the Risk of Allergy in a Dose-dependent Fashion (2018). Kids in homes with pets showed lower levels of sensitisation both to those animals and to pollen, and having more pets could offer greater protection.¹⁰ 

Allergy experts also believe that introducing peanut and other trigger foods to babies from four to six months old can help protect them from developing food allergies. Talk to your GP first, especially if your baby already has a food allergy or eczema.¹²

What are common allergies in children?

It’s possible to develop an allergy to nearly any substance but some allergies are more common than others. These include: 

• Respiratory allergies (outdoor): Also known as seasonal allergies because they only happen at certain times of the year. Hay fever symptoms can be an allergic reaction to tree pollen, grass pollen and weed pollen, or mould.⁹
• Respiratory allergies (indoor): Also known as perennial or year-round allergies. Triggers include dust mite waste, pet dander and indoor mould.⁹
• Food allergies: An allergic reaction to foods, especially eggs, cow’s milk, peanuts, tree nuts, wheat and shellfish.¹⁴
• Insect bites and stings: Bees, wasps and other stinging insects can trigger allergies in children with their venom.¹⁵ Mosquitoes and other biting insects inject saliva, which children may react to.¹⁶

Allergy symptoms in children

Each child experiences allergy differently, depending partly on how they’re exposed to their trigger but also what that trigger is.⁴ Allergic reactions to a respiratory allergen (like pollen), food or an insect sting have common signs and symptoms that parents can look out for – and report to the doctor. 

Respiratory allergy symptoms

Respiratory allergies cause similar symptoms to infectious rhinitis or cold. These can include:⁵ 

• Itchy, watery, or red eyes
• Stuffy nose, nasal congestion
• Itchy, runny nose
• Sneezing
• Coughing

You might also see your child rubbing their eyes a lot. Another common sign of respiratory allergies is the allergic salute. This is when kids rub their nose upwards with the heel of their hand, which can give them a crease over the bridge of their nose.⁹ 

Other symptoms linked to respiratory allergies

Respiratory allergies can cause mild local symptoms in the face, mouth and throat when your child eats certain fresh foods. It’s called oral allergy syndrome (OAS) or pollen food syndrome (PFS), and a common example is birch pollen allergy and apple. The proteins are so similar that the food triggers a cross-reaction.⁵

Speak to your doctor if this is what’s happening to your child.

Food allergy symptoms

Food allergy symptoms usually start very soon after eating but there can also be a delay, depending on the type of reaction. Some warning signs include: ¹⁴

• Tingling or itching in the mouth
• Itchy skin or raised rash (hives)
• Swelling of the face, mouth, throat or other parts of the body
• Difficulty swallowing
• Wheezing or shortness of breath
• Feeling dizzy and lightheaded
• Feeling sick (nausea) or vomiting
• Abdominal pain or diarrhea

Food allergies are the most common cause of severe allergic reactions in children.¹⁷ These reactions are called anaphylaxis (see below).

Insect allergy symptoms

It’s normal to get an itchy red raised bump, which may be harder to see on black or brown skin.^15,18 Kids who are allergic to venom from bees, wasps and related insects have a more intense reaction. The swelling is over 10cm across and may affect the whole arm or leg, depending where the sting was.¹⁸ After food allergies, insect stings are the next most common anaphylaxis trigger in kids.¹⁷

What is anaphylaxis and why do kids get it?

Anaphylaxis is a sudden severe allergic reaction that can be life-threatening and always requires emergency treatment. Allergies that put children at higher risk include food, insect stings, drug and latex. An anaphylactic reaction affects their whole body (systemic) and it’s vital to spot it as early as possible.¹⁹

Around 92% of kids across all ages show skin symptoms (according to Anaphylaxis in Children and Adolescents: The European Anaphylaxis Registry , 2016).¹⁷ The reaction can also affect their stomach, breathing and their circulation. Here are the common signs and symptoms:¹⁷ 

• Flushed or pale skin, itching, fast-spreading hives
• Swelling of the tongue or throat
• A weak or rapid pulse
• Diarrhea, feeling or being sick, abdominal pain
• Drop in blood pressure (hypotension)
• Narrowing of the airways, which may cause wheezing, coughing and trouble breathing 
• Dizziness or fainting
• Sudden behaviour changes

Read more about anaphylaxis in children at different ages.

Diagnosing a childhood allergy

Getting a clear diagnosis from the doctor is an important step for managing allergies in children. You can explain when your child gets symptoms, how severe they are and what seems to trigger them. Your GP will ask about their medical history and family allergies and may suggest allergy testing.^2,4 

A skin prick test or a blood test can help make the diagnosis.¹

How to manage allergies in children

Your doctor will work with you to come up with a treatment plan. The precise details will depend on the trigger but managing your child’s allergy is likely to involve these elements:²⁰

• Avoiding their allergens wherever possible
• Finding the right short-term symptom relief
• Thinking about retraining the immune system with allergy immunotherapy
• Safeguarding children at risk of anaphylaxis with a medication to use in emergencies

Helping your child avoid their allergens

Avoidance is an essential part to managing any allergy.²⁰ But no child wants to be told they have to stay indoors and can’t play football in the park when pollen counts are high. Or that they must never accept snacks if they have a food allergy. Dust mites love soft toys but saying no teddy in bed is not going to be popular either.⁵ So, pick your battles and negotiate. 

Maybe they can meet friends somewhere indoors or at a different time when pollen isn’t at its peak. Send them to school with yummy but safe snacks to share. And agree on a regular bath-time in the washing machine for teddy (or a spell in the freezer if he doesn’t like getting wet – check the washing instructions).⁵

There’s stuff you can do behind the scenes too, all depending on their allergy. Watch the pollen forecast, use mite-proof covers for your child's bedding, and talk to anyone who’ll be in charge of your child about their allergies.⁵ Talk to your child too. 

Short-term symptom relief for kids

Short-term relief options for kids are the same as for adults with allergy symptoms – antihistamines, corticosteroids, Leukotriene receptor antagonists, mast cell stabilisers and decongestants.²⁰ Ask your doctor what’s best for a child of their age with their specific symptoms. Allergy medicine for children can come in many forms – for example tablets, liquids, nasal sprays and creams – and over the counter or on prescription.

Always read the patient information leaflet carefully so you know how much allergy medication to give your child and how often. 

You can also try drug-free remedies to support treatment. Saline nasal sprays help loosen and thin mucus if your child has a blocked nose. They can help flush out allergens and may also make short-term allergy medicines like antihistamines work better. ²¹ Try soothing itchy eyes with saline eyedrops or artificial tears.⁵

Long-term symptom relief with allergy immunotherapy

Allergy immunotherapy or desensitisation is a course of treatment to teach a child’s immune system that their allergen is not the enemy. Controlled doses of the trigger help their body learn to tolerate the substance. The goal is fewer symptoms during and after treatment, so less need for short-term relief medication. ²²

The treatment is available for respiratory allergies like pollen, dust mite and pets.⁴ You may see your child’s symptoms start to improve after a few months as their body begins to get used to the trigger. But the immune system needs time to relearn and remember so treatment usually lasts three to five years. Immunotherapy can also reduce the risk of anaphylaxis for kids who are allergic to insect stings or peanut.²²

Allergy immunotherapy can be given as tablets that dissolve in seconds under the tongue or drops (SLIT) or as injections under the skin (SCIT). Peanut treatment is taken orally.⁴ Your doctor can tell you what the options are for your child. It depends on age, allergy and eligibility. Immunotherapy is not usually given to kids under the age of five.²³

Emergency treatment for anaphylaxis

If the doctor thinks kids are at risk of an anaphylactic reaction, they’re likely to prescribe an adrenaline nasal spray or auto-injector. Make sure your child carries two devices with them at all times as one dose may not be enough. They must still go to the hospital, even if the emergency treatment makes them feel better, in case of a secondary delayed anaphylactic reaction.¹⁹

Practise at home with a training nasal spray or auto-injector and get your child to do the same when they’re old enough. It’s also a good idea for them to wear an allergy alert bracelet. And make sure anyone looking after them knows how to keep them safe from anaphylaxis and what to do if it happens. That is, give adrenaline and call 999.¹⁹ It’ll all be in your child’s allergy plan, which you can share with daycare, nursery or school, anyone running activities and trips, even other parents hosting playdates. 

The short version

Allergies in children are the result of an overactive immune system, which tries to fight otherwise harmless substances.⁴ Common allergens include pollen, dust mites, mould, certain foods and insect bites and stings.⁹ Respiratory allergies triggered by airborne allergens usually cause an itchy, runny or stuffy nose as well as itchy, watery eyes.⁵ Food allergies can cause various digestive symptoms but also skin reactions.¹⁴ In children food allergies and insect sting allergies are the most common causes of anaphylaxis, a severe allergic reaction.¹⁷

Allergies tend to run in families.⁹ They often start with eczema in very young children. This might be followed by food allergies in toddlers. Hay fever and other respiratory allergies typically begin in school-aged children and can lead to allergic asthma. This is called the atopic or allergic march.² 

It's important to communicate your child's symptoms and their frequency and severity clearly to your doctor. It helps make a diagnosis and get your child the best care for their specific allergy. That could be medication such as antihistamines or retraining the immune system with allergy immunotherapy.²² Getting to the root of the problem early may help stop symptoms from progressing.¹ 

Parents know their kids inside out. They can spot when they’re unwell or unhappy or when something isn’t right. So if you think your child might have allergies, or that their current allergy treatment isn’t working, ask for help.