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Last updated: 17.06.19

How do you know if you're having an allergic reaction to food?

Food allergies are surprisingly common, with at least 1 in 20 people having at least one. They can range from being fairly minor irritations that you might not even be aware of, to the triggers of life-threatening illnesses. One of the more interesting points about allergies is that, while more common in children and infants, they can develop at any age. And it’s entirely possible to become allergic to a food that you’ve eaten all your life, including things like shellfish, milk, eggs and nuts. As a result, it’s important for people to have a basic understanding of allergies and how they can manifest. Being able to recognise an allergic reaction means that you can quickly seek medical advice, whether for a minor concern or in the event that you believe you’re suffering from anaphylaxis. Let’s take a look.

It’s helpful to know that there are two types of food allergy. They are Ig-E-mediated food allergies and non-IgE-mediated food allergies. The former is more commonly known, and the two types present themselves in different ways. It’s also possible to have a mixture of the two, which is more prevalent in children. Below, we’re going to cover each type.

IgE-mediated food allergies

The most common form of food allergy is IgE-mediated. These are allergies which show symptoms after seconds or minutes of eating, and are triggered because the immune system produces an antibody called immunoglobulin E (IgE).

Symptoms of IgE-mediated food allergies include the following:

●Itching or tingling in the mouth

●Rashes on the skin, or itchiness, or redness

●Swelling, often in the face or mouth

●Dizziness and nausea

●Difficulty swallowing or breathing


●Sneezing and itching in the eyes

●Stomach pains and diarrhoea


Anaphylaxis is generally the result of an IgE-mediated food allergy, and is a medical emergency with potentially life threatening implications. It is essentially a very severe reaction to a food allergy, again involving the body’s own immune system. Should you or anyone else present with symptoms of anaphylaxis, it’s essential to call 999 and seek emergency medical help immediately.

Symptoms of anaphylaxis include the following:

●Swelling in the mouth, particularly the tongue

●Severe breathing difficulties

●A tight chest

●Dizziness and fainting

●Difficulty swallowing


Note: Anaphylaxis is often erroneously called anaphylactic shock. The two conditions are not the same; anaphylactic shock is a type of shock caused by anaphylaxis. Shock is a medical emergency whereby a person’s blood pressure drops so low that oxygen is not properly supplied to the body.

Non-IgE-mediated food allergies

Non IgE-mediated food allergies are much harder to identify and diagnose because they generally don’t have immediate symptoms. In some cases it can actually be days between coming into contact with or eating a food you’re allergic to, and the symptoms presenting themselves. Immunoglobulin E is not the cause of these reactions, but rather other cells in the immune system.

Symptoms of non IgE-mediated food allergies include the following:

●Eczema or an itchy rash




●Abdominal pain and cramping

Food allergy awareness

Food allergy awareness is a very important part of training for those that work with food, whether in manufacturing, retail or catering. Here at Virtual College we’re pleased to offer a training course in this subject. Aimed towards anyone that works with food, it covers important information on the biology of food allergies, what the law says about business’ allergy responsibilities, as well as some of the essentials when it comes to reducing the risk of an allergic reaction. Click here to find out more about this useful course.