An allergy is exacerbated response of the immune system in contact with foreign body, usually harmless substances. The immune system of sensitive people recognize these elements as harmful and as a result trigger. Causing allergic substances are called allergens. Example of allergens are pollen, dust mites, microscopic mites, pollen, mold, certain foods and others.
To understand the nature of allergy you have to remember that allergens are substances foreign to the body which, in more sensitive individuals can cause a strong reaction of the immune system.
When an allergen comes into contact with human body, it causes the immune system is activated to its buffering action. This happens most often in people who are allergic to this allergen. If you react to allergens, which are basically harmless to most people, then you suffer from allergies and are allergic or atopic.
The term allergy was introduced in medicine by the Austrian pediatrician Clemens Pirket. In it he indicated as beneficent reaction of the immune system to the action of allergens and harmful ultra-sensitivity of the organism to the same. The term allergy comes from the Greek words “allos”, meaning different or changed, and “ergos”, meaning job action. In rough translation meaning of the word allergy is the response.