An allergy is an abnormal reaction of the immune system to a substance that it cannot tolerate. If some so called atopic grounds are predisposed to it, allergies are more and more numerous and common, whatever their origin, and affect, year after year, more and more people, all ages included. They can be respiratory, dietary, or drug-induced, and cause symptoms of varying severity.

Our modern environment, active or passive smoking and our abundantly polluted atmosphere are not directly allergenic, but they greatly promote it.

Several recent studies have shown that there is a link between pollution, respiratory allergies and asthma, particularly by causing irritation to the respiratory system.

In addition, our lifestyle is directly related to the modification of the immune system. The hygienist thesis denounces excessive vaccination and antibiotic therapy, in addition to excessive hygiene. This almost totally aseptic way of life strongly limits the contact, however essential, between the child and the external micro-organisms. The immune system becomes dysregulated and does not develop in an ideal and optimal way.

In our less and less ventilated homes, the humidity level is often high, which increases the proliferation of dust mites. These small microscopic beasts of the arthropod family are responsible for many allergic reactions, about 60% in children and over 30% in adults.

These allergies, which are often blamed on dust, manifest themselves in different ways; by rhinitis or asthma, if they penetrate the respiratory tract, by itching and eczema, if they come into contact with the skin or, less frequently, by asthma and angioedema (subcutaneous) when ingested with poorly preserved foods or in certain flours. These symptoms may also be accompanied by conjunctivitis.

Warm and humid environments are definitely in demand. Like dust mites, mold can invade our homes and create allergic reactions. The inhalation of spores causes manifestations such as asthma, rhinitis or conjunctivitis.

With more than 3% of the population affected, our friends the animals are also concerned and not only because of their hair. Saliva, urine and sebaceous gland secretions are also involved. It is not necessary to be in direct contact with the animal to express different symptoms: asthma, urticaria, eczema, conjunctivitis or rhinitis.

Pollinosis, also known as pollen allergy or "hay fever," affects approximately 20% of the Western population. Although it is usually predominant in adolescents and young adults, it can occur and happen at any age. Again, pollution exacerbates the problem by weakening the surface of the grains, allowing increased release of allergenic substances. Runny nose, sneezing and itchy eyes are common manifestations of pollen rhinitis. Asthma very often accompanies them.