Allergies in Childhood

An allergy in childhood happens when a child’s immune system mounts an exaggerated response to a substance that is harmless to most other people. The response may show up as redness, itching, a blocked nose, wheeze, watering eyes or abdominal pain. Childhood allergies are among the most common health problems of the early years and one of the areas where parents feel most helpless.

This page explains how allergies develop, at which ages and in whom they are more likely, how allergic rhinitis differs from asthma and eczema, what you can do at home, and when a doctor should be involved. Nothing here is a diagnosis or a treatment recommendation, because what a child is allergic to can only be established by a doctor, from the history, the examination and, where necessary, tests.

How an allergy in childhood develops

The immune system exists to recognise what comes from outside the body and to defend against it. Allergy usually follows a recognisable sequence: a child first encounters a substance, the immune system marks it as a threat, and antibodies are produced on contact. This learning process — the moment the immune system identifies something as an allergen — often takes place during the first years of life.

The allergic reaction appears at the next encounter. Immune cells respond far more quickly and more forcefully, and an inflammatory reaction starts in the eyes, nose, skin, airways or the lining of the gut. How mild or severe it is depends on which organ is involved: reddening of the skin is uncomfortable, but the same process in the airways is far more urgent.

None of this is contagious, and it is not a sign of a weak immune system. The immune system is doing its job rather too well, treating harmless substances as threats.

At which ages and in whom they occur

Food-related reactions are seen most often in early childhood, partly because the lining of the gut has not yet matured. After the age of seven, airway allergies come to the fore, as children meet dust, pollen, animal dander and cold air far more intensively.

There is also a familial element to the tendency towards allergy. If a mother or father has allergic rhinitis, asthma or eczema, a similar pattern is generally more likely to appear in the child, which reflects an inherited susceptibility of the immune system rather than any fault. Eczema, allergic rhinitis and asthma also often occur together, because all three can develop on the same allergic ground.

Telling allergic rhinitis, asthma and eczema apart

Separating these patterns matters, because it points towards the right next step.

• In allergic rhinitis the leading features are a blocked nose, repeated sneezing, clear watery discharge and itchy, watering eyes. Symptoms are usually tied to the season: tree pollen in spring, grass and weed pollen in summer, and indoor triggers taking over in winter.
• In asthma the most characteristic finding is wheeze present even when the child is calm. Cough, breathlessness and chest tightness often come with it, and exercise or cold air can make symptoms noticeably worse.
• In eczema the skin shows itchy, red patches that sometimes ooze and crust. The areas involved change with age: the face and scalp in infancy, the creases of the elbows and knees in older children, and the back and hands in adolescence.
• When a food is suspected, symptoms usually appear shortly after it is eaten — abdominal pain, vomiting, diarrhoea or a rash. Working out which food is responsible is usually not something a family can do on its own.

The timing and pattern of symptoms help in making this distinction. Complaints that appear in certain months and return in waves point to a seasonal pattern; complaints that run all year but become more frequent during periods of upper respiratory infection may be infections sitting on an allergic background. Describing your child’s recent history is therefore valuable at the consultation.

What can be done at home

Measures at home aim at reducing exposure and making daily life easier. They do not replace the doctor, but they can change how the day goes.

• Nobody should smoke indoors. Tobacco smoke is the environmental exposure children meet most often, and it clearly increases respiratory complaints.
• To limit dust allergens, pillows and bedding should be washed at high temperature and pillow covers changed frequently. Harder-wearing floors instead of carpets, and regular ventilation, also help.
• Where there are pets, they should be kept out of the bedroom; preventing access to the bed is one of the most effective ways of reducing allergens.
• The child’s room should be free of perfume, deodorant, room sprays and strongly fragranced cleaning products, which can trigger wheeze in children with airway problems.
• Hands, face and hair should be washed after coming in from outside, reducing contact with allergens carried on the fingers — especially in children who rub their eyes and mouth.
• Dietary restriction should not be rushed into. If a particular food is suspected, do not limit your child’s table on your own initiative: removing foods can take away nutrients needed for growth, and the decision belongs to the doctor.

When to see a doctor

Some patterns can be watched and waited out; others cannot wait. The signs below can point to a severe allergic reaction (anaphylaxis); if they appear, call 112 or go to the nearest emergency department immediately:

• Difficulty breathing, wheeze, the chest pulling in between the ribs, or lips and face turning blue.
• Sudden swelling of the face, lips, tongue or throat, a change in the voice or difficulty swallowing.
• Vomiting, abdominal pain and a rash covering the body occurring together shortly after a meal.

In the situations below, book an appointment and see a doctor:

• A persistent cough that disturbs sleep, daytime tiredness, repeated ear infections or a fall in growth should prompt assessment for allergic causes.
• Symptoms that clearly rise and fall with the seasons follow a pattern that infections do not, and this should be discussed with a doctor.

Common mistakes

1. Trying something ourselves as well. Applying remedies recommended by those around you, herbal mixtures or over-the-counter medicines to your child without advice may be simply wrong, and may make a reaction worse.
2. Assuming every sneeze is an allergy. Upper respiratory infections are very common and produce similar symptoms; that distinction is for a doctor to make.
3. Summarising the history too loosely. When several weeks of symptoms are compressed into one sentence, it becomes harder to work out which trigger is involved. Photographs, short video clips and a simple diary make the account richer.
4. Using over-the-counter medicines regularly. Antihistamines suit some situations, but the choice and duration are for the doctor to decide; a medicine taken before a cold has been distinguished from an allergy can delay recovery.

Common questions

Is it an allergy or just a cold?

A few points are looked at: whether symptoms track the seasons, whether there are signs of infection such as fever or lethargy, and whether the nasal discharge is clear or coloured. The doctor makes this distinction from the examination and, where needed, from a few tests.

Should I ask for an allergy test?

Allergy tests only carry meaning when read together with the clinical history. A positive result does not mean the substance identified is causing a reaction in your child, and whether any investigation is needed is the doctor's decision.

Should I cut something out of my child’s diet?

Not on your own. Taking a food out of the diet can also remove nutrients the child needs to grow. If you think a food is involved, tell the doctor and work out a plan together; nutrition needs particular care throughout.

Does an allergy affect a child’s growth?

Allergic problems that are not well managed can disturb sleep, which affects appetite and growth indirectly. Airway symptoms that are not followed regularly also weigh on daytime activity, so tracking the symptoms and having the treatment adjusted both matter.

Can a child with allergies still do sport?

Yes. Children with allergies can carry on with regular physical activity. What to watch during exercise and what to do when symptoms appear are best planned with your doctor; adjusting the activity to conditions is generally healthier than stopping it altogether.