2024 - Food allergy in adults

What is it about ?

We talk about food allergy when foods or food ingredients like dyes and preservatives trigger allergic symptoms. In the event of an allergic reaction, the body produces an abnormal amount of antibodies against these products.

The foods that most frequently cause serious reactions are nuts, seeds, fruits and vegetables, but also milk and wheat. Certain medications, such as anti-inflammatory drugs and antihypertensives, as well as alcohol can play a role in the development of an allergic reaction to foods.

People who are allergic to dust or pollen also have a higher risk of developing an allergic reaction to certain foods, because both the food and the dust contain proteins that share similar characteristics. This is called a cross allergy. For example, a person allergic to birch pollen is more likely to be allergic to fruits, root vegetables, legumes, and nuts.

What is its frequency?

3 to 4 in 100 adults have a food allergy. Studies show that 20 in 100 people avoid certain foods because they show symptoms when eating them. However, that doesn’t always mean it’s an allergy. In these cases, we will speak of a pseudo-allergy.
Symptoms usually start in childhood, but an allergy can also start in adulthood.

How to recognize it?

A food allergy can trigger both local symptoms and general symptoms. Oral allergic syndrome (ODS) is common. This is a set of symptoms (a syndrome) that occur following contact with food. These symptoms can be, for example, tickling of the lips and tongue, swelling of the throat. They can be triggered, for example, by eating raw fruits and vegetables. People who are also allergic to trees (birch) particularly suffer from it. In addition, gastrointestinal symptoms are often present, such as nausea, vomiting, diarrhea, and abdominal pain. On rare occasions, a potentially fatal extreme reaction (anaphylactic shock) may occur with a drop in blood pressure, difficulty breathing and a rash with itching. This reaction sometimes occurs when a food allergy is combined with exercise. The reaction only occurs if you exert yourself within 4 hours of eating.

Other pre-existing allergic symptoms may then also worsen, such asasthma, the hay fever or skin rashes (eczema).

How is the diagnosis made?

The doctor will first carefully check which foods are triggering the symptoms, what your complaints are, how severe they are, how long it takes for them to appear, and how long they last. He will also check if you have any other allergies and if there are any cases of allergies in your family.

The most important additional test is the skin allergy test (prick test). Droplets containing a suspicious food are applied to the skin. With a fine needle, the skin is pricked through the gout. In case of allergy, a swelling (a blister) red, sometimes irritating (e), appears after about fifteen minutes. If this test is not available, a blood test will be carried out with the determination of specific antibodies directed against the suspect foods. If you think of an association between a food allergy and a respiratory allergy (cross allergy), you will also be tested for pollen allergy.

You may react to a test even though you have no symptoms when you eat the food being tested. In this case, we will speak of a non-significant allergy: you are indeed allergic, but it does not matter in relation to your diet. So you can eat the food in question without worrying.

What can you do ?

Avoid foods that trigger symptoms. It can be helpful to write down everything you eat for a while to find out which ingredient is causing you concern. If the symptoms are severe or you don’t know what you’re allergic to, get tested first.

Indeed, the fact of not tolerating certain food components is far from always being synonymous with allergy. For example, a irritable bowel, a Lactose intolerance or to gluten (celiac disease) can trigger the same type of symptoms, although there is no question of allergy.

What can your doctor do?

If it is not known which food triggers the symptoms and if the symptoms are not too severe, the doctor sometimes suggests an elimination diet (avoidance diet). A number of foods are then eliminated from the diet. If the symptoms disappear, they can be added to the diet one after the other. The product that causes the symptoms to reappear is probably the cause of the allergy.

In case of mild forms of allergy, the doctor may prescribe an antiallergic drug (antihistamic). In case of severe symptoms, the doctor sometimes gives a single dose of cortisone or a short course of cortisone.

People who have had a serious, life-threatening reaction (anaphylactic shock) should always carry an adrenaline injector (Epipen®, Jext®) with them. Thus, they can self-inject if the situation happens again. The pharmacist will explain to you how it works. The doctor will also explain to you whether treatment for a pollen allergy may help.