top of page

Food allergies-intolerances
& Pseudo allergies (mast cell hypersensitivity)

The term “food intolerance” encompasses different chemical processes by which we become intolerant to a food.
For example it can be linked:

  • Insufficient enzymes to digest the food (lactose or histamine intolerance)

  • The fact that the food feeds bacteria that produce gas (SIBO)

  • The fact that the food irritates the mucous membrane (wheat lectin, wine tannins, peppers, bile)

  • The fact that the food causes a chronic inflammatory reaction (see IgG tests)

  • The fact that the food causes a histamine reaction (see IgE tests)

Immediate allergies (IgE)

These are allergies that occur seconds or minutes after ingesting the food. The responsible allergens can be identified by carrying out provocation tests with fresh food on the lip or by carrying out skin prick tests or in blood samples (recombinants).

This search for type I allergies is very important to carry out because in food intolerances, different chemical processes can be involved by which we are intolerant to a food.

We have in our center a pediatric allergist with a lot of experience in this field and who performs these tests at the center

Semi-delayed hypersensitivity reactions (IgG)

“Allergic” reactions will occur a few hours to a few days after ingesting the food. So they are much more difficult to recognize. The diagnosis will be made using a blood test. These semi-delayed hypersensitivity reactions can be the cause of a large number of autoimmune inflammatory diseases such as inflammatory bowel disease, eczema, psoriasis, polyarthritis, asthma, allergic rhinitis, etc. . The patient will receive during his consultation a request for analyzes with which he will have to go to a sampling center.

Attention !It is not because food IgG are high that one is necessarily allergic to this food. It may simply be a reflection of the state of the intestinal wall.

As mentioned at the beginning, allergies should not be confused with food intolerances either. The foods we are intolerant to do not trigger an immune system reaction, but they cause us digestive problems. Examples: lactose intolerance, fiber intolerance, acidic foods, etc.

Pseudo-allergies  or Mast cell hypersensitivity

These are very varied manifestations that vary over time (cough, tachycardia, allergic skin manifestations, headaches, stomach aches, hypersensitivity to odors, etc.) which are the consequence of an excessive production of histamine  in response to excessive reactivity of the cells that produce this histamine (mast cells).

Looking for solutions

To find solutions, it is always necessary to start by establishing a diagnosis.


This is why we are going to try to distinguish between type I and type III allergies, food intolerances (lactose, histamine, FODMAP), mast cell hypersensitivity and its causes (microbiota).

Some exams can be used for this, such as:

  • Skin allergy tests (Prick tests with fresh foods) +  RAST blood (IgE) tests with recombinants

  • IgG test

  • Metagenomic analysis of microbiota – role in histamine hypersensitivity

  • Urinary assay of candida metabolites - role in histamine hypersensitivity

  • Dosage of short chain fatty acids (postbiotics emitted by the microbiota) which modulate the allergy.

  • Breath test for lactose, lactulose, measurement of fecal histamine, and DAO

Our Experts


Médecin nutritionniste


Médecin nutritionniste

bottom of page