Food allergies – an overview

Over a third of parents believe that their child suffers from adverse reactions to food, but just how common are childhood food allergies, and what might trigger an attack?


Food allergies have become a hot topic for parents of young children. As an adult, the chances of you having a food allergy, as opposed to a food intolerance, is around one in one hundred, but in children under four they are more common. And with the potential for allergic reactions to be life-threatening, it’s no wonder that many parents approach the weaning stage with trepidation.


What is a food allergy?

A food allergy is a reaction that occurs when your child’s body mistakes a harmless substance within a food for an allergen: something that causes an allergic reaction. If your child has a food allergy, his immune system will react to certain foods by producing antibodies (proteins that fight harmful invaders that attack the body). This reaction can cause a variety of unpleasant symptoms, from feeling sick to swollen lips or even breathing difficulties.

Some allergic reactions can happen the first time that your child eats a trigger food, whereas others develop over time. The reaction may become stronger each time your child is exposed to the problem food and in rare cases, can be life threatening.

How common are food allergies?

According to the medical website NetDoctor, around a third of parents or carers avoid feeding their children certain foods because they believe they cause an allergic reaction. But in fact, researchers estimate that the true figures are much lower, with somewhere between three and eight per cent of children suffering from a genuine allergy.

Most children will outgrow their food allergies before the age of three, but if your child is allergic to certain foods, like peanuts and fish, it’s less likely that he’ll grow out of his allergy. And while the chances of your child developing a food allergy are relatively slim, it’s more likely if there’s a family history of allergies, including asthma, eczema and hay fever.

What are the most common trigger foods?

According to a report by the Committee on Toxicity, 90 per cent of food allergies in children are caused by cows’ milk, eggs, wheat, peanuts, tree nuts (e.g. walnuts, brazil nuts, hazel nuts), fish and soya protein. Certain additives such as tartrazine are also implicated in food allergies, but most food allergies in children are caused by naturally occurring substances rather than man-made ingredients.

How might your child react?

Allergic reactions to food can be broadly divided into three categories:

  • Immediate reaction: the allergic symptoms develop quickly, usually within an hour of eating the trigger food.
  • Delayed response: the reaction flares up between two and 24 hours after exposure to the problem food.
  • Anaphylactic shock: a sudden and severe allergic reaction.

Your child may not always react in the same way to a particular allergen: for example, milk, egg and peanuts can cause either an immediate or a delayed response.

Anaphylaxis, or anaphylactic shock, is a sudden, severe allergic reaction that affects the whole body. The most common symptoms of anaphylaxis in children are breathing difficulties and wheezing. Anaphylaxis can be triggered by eating even a tiny amount of a problem food – or, in extreme cases, just by touching that food – and requires immediate medical attention. If you suspect an anaphylactic reaction, call 999 immediately.

Outgrowing food allergies

The majority of children will grow out of their food allergy, usually by the age of three. If your child has a confirmed allergy, his GP or dietician may advise testing him with small amounts of his trigger food once he reaches the age of three, increasing the quantities gradually if he doesn’t react.

Some parents find that as their child gets older, he outgrows his food allergy but develops a new allergy in its place, for example to pollen or dust mites.


If your child suffers from an anaphylactic reaction to food, it’s unlikely that he will outgrow the condition, and he’ll probably need to avoid the trigger food and carry emergency Epinephrine – the drug that reverses the reaction – for the rest of his life.

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