Allergies versus intolerances

baby eating corn
There is a lot of talk in the news about allergies and intolerances which can be very confusing. It can be hard to know what the difference is between the two and why does it matter? Whilst allergies and intolerances seem similar, they are different and it is good to know about them so that you can be prepared if you ever come across one with your child.

The table below highlights the main differences between the two; however it is important to note that this is intended as advice only and if in doubt always contact your heath visitor or GP for more information.

Food Allergy Food Intolerance
What is it?
An adverse immune response to a specific protein within a food.
An adverse bodily response to a component within a food (not necessarily protein) with no immune involvement.
Common or rare? Rare, but risk is higher in families with a history of allergy.
More common than an allergy but still unusual in children.
What causes it?
The immune system thinks the protein in the food is harmful and reacts to it, causing symptoms (see below).
There are a number of causes; sometimes a lack of enzymes means food can’t get digested, or sometimes foods can cause symptoms on their own.
A reaction can be caused by the smallest traces of the foodstuff.
Usually a reaction to teaspoon amounts of the food.
Redness, swelling, difficulty breathing, skin reactions including urticaria (hives) and anaphylaxis, but can be many more.
Headache, bloating, stomach ache, diarrhoea, sickness. No anaphylaxis.
How is it diagnosed? Generally; look at previous medical conditions and rule out other causes. Then either a skin prick test (SPT) or blood test (called a RAST) or skin patch test (all by GP or allergist). Could involve; look at previous medical conditions and rule out other causes. Then either keeping a food and symptom diary, or ‘exclusion diet’ where foods are avoided and then re-introduced to see if they cause symptoms.
Is there a cure? Food will need to be avoided for life – however some children can ‘grow out’ of their allergies. If the intolerance is severe the food may need to be avoided for life, or limited to little amounts.
How is it managed? For some, mild symptoms can be controlled by anti-histamines. Adrenaline may need to be carried if severe allergy. If the food is a major part of the diet nutritional advice may be needed to ensure diet is healthy. Re-challenges may be requested under medical supervision to see if allergy persists into adulthood.  If the food is a major part of the diet nutritional advice may be needed to ensure diet is healthy. Adrenaline is not required. As some children can ‘grow out of’ food intolerances re-challenges may be requested under medical supervision.

What is anaphylaxis?

Anaphylaxis is the name given to a type of allergic reaction which affects the whole body. It can be life-threatening. Thankfully it is very rare; however if it occurs it requires immediate medical treatment and it is for this reason that all allergies should be taken seriously.

Anaphylaxis usually occurs within a few minutes of exposure to the allergen but can take a few hours to develop. The symptoms can be varied but include skin redness, urticaria (hives) appearing on the body, mouth and throat itching or swelling, difficulty in swallowing or speaking, heart beating faster, wheezing or worsening of asthma, feeling sick or vomiting, drop in blood pressure (may feel weak or fall down) and unconsciousness.

If you believe that your child may be experiencing anaphylaxis then immediately seek medical advice by calling 999 and follow their instructions. Usually it is treated by adrenaline (an EpiPen), and some people who have had anaphylaxis in the past carry this with them just in case.

What should you do if you think your child has an allergy/intolerance?

If you suspect that your child may have an abnormal reaction to a food it is important to see your GP to discuss this. Sometimes what looks like an allergy or an intolerance might be something different so you don’t want to take things out of your child’s diet until you know for sure it is the cause.

If the symptoms were very obvious to one specific food (for example, an egg) then it may be wise to avoid giving them egg until you have a chance to speak to the GP. Even if you do this and the symptoms stop, you should still book an appointment to see your GP so you can have your concerns confirmed and properly diagnosed.

It may help you to write down what they ate and exactly what happened so that you don’t forget anything which may be important when you see your doctor, this will also help them to make the right diagnosis.

What sorts of foods are likely to cause an allergy?

Any food containing proteins has the potential to cause an allergy, however there are some which are more common culprits than others, these include; peanuts, tree nuts, fish and shellfish, cow’s milk, eggs, soya and wheat.

What sorts of foods are likely to cause intolerance?

It isn’t really known what makes a food likely to cause intolerance, however lactose, a milk sugar, is known to cause intolerance. This is due to having less of the enzyme in your body which breaks it down.

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