Skip to content

What’s the Difference Between Allergy and Intolerance?

It’s Allergy Awareness Week...

...and since here at Erudus we’re dedicated to all things allergy related you can find a host of features covering subjects such the most common new allergens, how allergens hide in alcohol and what it’s like to eat out as an allergy sufferer - as well as plenty of allergy-friendly menu ideas in The Erudus Recipe Book.

We’re also taking this opportunity to go back to basics, and explain what an allergy is, its effect on the body, and how it differs from a food intolerance - things it really benefits Caterers and consumers alike to know.

So read on to find answers to some of the most common questions about allergies and intolerances...

What’s an allergy?

An allergy is a reaction, the body’s immune system reacting to a specific substance (often a food) as though it is harmful.

The immune system is there to defend the body against ‘foreign invaders’, and in the case of allergies it misidentifies a harmless substance as a foreign invader - a danger. Allergic reactions can range from mild to severe, and in extreme cases lead to life-threatening anaphylaxis.

Allergies are generally more common in children than adults, though you can develop an allergy at any stage of life, and the number of sufferers is increasing every year (this may be because living conditions have become cleaner and our immune systems are less used to be exposed to germs).

What’s an intolerance?

An intolerance is the (sometimes delayed) reaction of the body - usually the digestive system - to a particular food or substance.

Food intolerance symptoms can be unpleasant or inconvenient but they are not fatal, and the sufferer can generally tolerate small amounts of their trigger substance.

Because of their link to the digestive system, intolerances are more common in people who suffer from IBS (Irritable Bowel Syndrome) and other digestive conditions.

What’s the difference between an allergy and an intolerance?

The fundamental difference between an allergy and an intolerance is that an allergy affects the immune system and can result in deadly anaphylaxis, and an intolerance does not affect the immune system.

They both can result in similar symptoms that are either painful or uncomfortable but they come from reactions to different systems within the body.

For those with an allergy, ingesting or coming into contact with even a small amount of their allergen can trigger severe symptoms, whereas most people with intolerances can consume small amounts of the substance without experiencing adverse affects.

People often mistake a food allergy for an intolerance and vice versa, but it is important for a sufferer and those they interact with to know which it is because allergy sufferers must carry an Adrenaline auto-injector (AAI) in case of anaphylaxis.

Even if previous reactions have been mild, someone with a food allergy is always at risk of the next reaction being life-threatening. Eating a microscopic amount of the food, or sometimes even touching or inhaling it, could lead to anaphylaxis. So anyone with a food allergy must avoid the problem food(s) entirely and always carry emergency injectable epinephrine.

Can an intolerance turn into an allergy?

An intolerance should not turn into an allergy, because they affect different systems within the body. People can develop new allergies as an adult, but this does not mean it is related to a pre-existing intolerance.

What is a food sensitivity?

A food sensitivity is when a person experiences an exaggeration of a substance’s normal affects. The NHS gives the example that ‘the caffeine in a cup of coffee may cause extreme symptoms, such as palpitations and trembling’.

What are common allergies?

Substances people are allergic to are called allergens. Common allergens include:

  • Pollen (grass, trees etc) - known as hayfever
  • Animals - dander, hair, feathers
  • Food and drinks (see below)
  • Dust mites
  • Mould
  • Chemicals found in common household products (detergents, soaps, cosmetics etc)
  • Insect bites and stings
  • Latex (gloves, condoms etc)
  • Medicines (aspirin, ibuprofen, paracetamol, penicillin and other antibiotics)

The 14 major food allergens

There are 14 major food allergens categorised by the Food Standards Agency (FSA) - Caterers and food businesses are legally required to be able to provide customers with accurate information on these allergens if they are included in any of the food products they produce, sell or serve.

They are:

What are the symptoms of a food allergy?

The most common symptoms of an allergy (and an allergic reaction) are

  • Irritated nose (sneezing, itching, running stuffiness)
  • Irritated eyes (watering, itching, redness)
  • Rashes (raised, red, itchy)
  • Swelling (in the lips, tongue, eyes or face)
  • Breathing problems (chest tightness, shortness of breath, coughing, wheezing)
  • Irritated stomach (nausea, vomiting, pain)
  • Irritated skin (dry, cracked, red)

Do a food allergy and food intolerance share the same symptoms?

Food allergies and food intolerances share some of the same symptoms, such as vomiting and a rash on the skin.

However, because a food intolerance does not affect the immune system like a food allergy does, sufferers are unlikely to experience the same breathing problems and swelling triggered by an allergic reaction.

Many symptoms of a food intolerance are linked to the digestive system. These include

  • Diarrhea
  • Stomach ache
  • Heartburn
  • Gas
  • Cramps
  • Bloating
  • Nausea and vomiting

How do you treat a food allergy?

The most effective way to treat a food allergy is by keeping away from the triggering allergen.

Of course, this is not always possible, and there are other precautions you can take and steps to take if an allergic reaction occurs. You can read about these in our guide to how to treat an allergy and our series 'What to do if a customer has an allergic reaction', which is packed full of advice from allergy experts.

You may also be interested in…

open wicker basket filled with eggs spilling out onto a dark wooden oak table and a small white feather
open wicker basket filled with eggs spilling out onto a dark wooden oak table and a small white feather

You may also be interested in…

Your Egg Allergy Cheat Sheet


You may also be interested in…

Menu board with  wooden gluten free options available sign
Menu board with  wooden gluten free options available sign

You may also be interested in…

Coeliac Awareness Week