maintenance. How do you get allergic to pollen? An allergy specialist decodes the mechanism that affects millions of French

La Dépêche du Midi: How does one become allergic?

Catherine Koike: We feel allergic on a genetically prone territory to allergies, often a parent or grandparent with allergies. It is an exaggerated reaction of the body to environmental allergens. But allergy symptoms take longer or less time to occur. So an overnight allergy is an acceptable idea! In people with allergies, there is an initial period known as ‘sensitization’ during which the body produces antibodies called immunoglobulin E (IgE) that are directed against proteins (allergens) found in dust mites, animals, certain foods, pollen, etc. Without provoking symptoms upon contact with the allergen. This so-called “sensitization” period can vary from a few months to several years. And when this contact is repeated over time, an allergic disease begins with the appearance of symptoms: cough, runny nose, difficulty breathing, food allergy with angioedema and even anaphylactic shock.

You estimate that in 2050, half of the French will be allergic. How do you explain that?

There is no longer a need to prove the exponential evolution of the number of allergy sufferers. Let’s not forget that over twenty years ago, it was estimated that one in four French people had an allergy. Currently, a third of the French are affected! This prevalence is increasing, projections put it, in about thirty years, at 50% of the population. Increasingly polluted air and global warming cause chronic respiratory irritation and increase the duration of pollen allergy. As for industrial and processed food, it leads to an imbalance in the intestinal microflora that favors food allergies.

We also know that the use of creams containing allergenic proteins (wheat, milk, egg proteins, etc.) increases the sensitivity of people with allergies, especially in early childhood. This is why people with atopic history – that is, those who are genetically prone to allergies – are advised not to avoid these types of cosmetics.

In your book, you talk about the new allergy. Is it possible to develop a new allergy during your life?

Allergies can occur throughout life, including late. We can see that more and more “multiple allergies” are developing. Pollens are reservoirs of allergens and lead to the so-called “cross-allergy” phenomenon. Your immune system will react abnormally when you ingest substances similar to those to which you are allergic. This phenomenon can later lead to a cross allergy between birch pollen and raw apple, for example. For these elements, the two allergens differ but have a nearly similar molecular structure. These are allergen proteins, from the PR 10 family. Over the years, we’ve discovered more and more allergenic families like the ones described, and recently explained in the South cross-allergies between cypress pollen, peach and citrus.