No one is safe. An allergy can occur at any age and become chronic if not properly treated.

In France, the number of allergic patients doubles almost every 10 years. Whether respiratory, skin or food, the allergy should not be taken lightly. If certain symptoms seem harmless ( hay fever , eye allergy, urticaria ...), they can progress to serious disorders: asthma , anaphylactic shock, severe eczema ...).

"One in three people with allergic rhinitis is likely to develop asthma within 10 years," says Dr. Isabelle Bossé, president of the French Syndicate of Allergists.

By 2050, half of the world's population will be affected according to the World Health Organization (WHO).

Pollution, n ° 1 enemy of allergies

The air is more and more stale, especially in the city. Industrial activities, automobile traffic, road transport and district heating emit gases and fine particles that irritate the airways and make pollens more allergenic. Nitric oxides and ozone modify the biochemical structure of allergens.

Tobacco also potentiates allergies. Its fumes increase the reactivity of the mucous membranes, which aggravates rhinitis, asthma and allergic conjunctivitis.

Rural areas are not spared either because pesticides are the cause of many allergic manifestations.

Allergies: global warming pointed the finger

With the warming of the climate, the winters are less and less rigorous. As a result, the pollination period is not only earlier but also longer. The aerobiological monitoring networks, which measure the evolution of the pollen concentration of the air, regularly observe this phenomenon.

Thus, during the 1970s, birch pollen appeared in Brussels for about ten days from April 15th. From now on, they appear from March 15th and persist for almost a month. The density of suspended pollen is also increasing.

"One foot of ragweed - a very allergenic herb - produced 5.5 g of pollen in the 1900s, it emits 10 g today," observes the National Observatory on the effects of global warming (Onerc). And that's not all: climate change is also changing the geographic distribution of some species, exposing many people to allergens they did not face before. Ambrosia, previously confined to the Rhône-Alpes region, is now established in the Massif Central, Burgundy and Gironde. Hence the appearance of new allergies in these regions.

Excess hygiene strengthens the allergic reaction

Living in an environment that is too sterile deepens the bed of allergies because the immune system is not properly educated at an early age. "Studies have shown that children raised in the countryside, so exposed early to miasma and allergens of animals suffer less allergies than city dwellers," says Pr Jean-François Bach, immunologist.

The same is true when exposure to microbes is limited. The body, unaccustomed to fight bacteria, overreacts inconsistently to allergens. For lack of reference, the immunity goes wrong and develops an allergic sensitivity. In terms of hygiene, excessive zeal is therefore contraindicated.