Allergy: Allergens and Their Effects

The concept of allergy was originally introduced in 1906 by the Viennese pediatrician Clemens Von Pirquet, after he noticed that some of his patients were hypersensitive to substances which were normally harmless. Pirquet called this phenomena 'allergy' which in Greek means 'other work'. Allergies were thought to be caused by an improper activation of the immune system. Substances that cause allergies are known as allergens. Different people are allergic from different allergens. For example, dust, pollen, insect stings, certain types of clothes, food, etc. The symptoms appear due to the part of immune system affected, binding an allergen to basophils (WBC). These cells ultimately release an inflammatory chemical called histamine. The histamine causes an allergic reaction and symptoms like inflammation, skin rash and constriction of the bronchioles. Allergies are common in the developed world, above 20 per cent of people are affected by allergic rhinitis (running nose), above six per cent of people have at least one food allergy, and above 20 per cent have allergic dermatitis at some point in life. Depending on the country, from 1 to 18 per cent of people have asthma. Rates of many allergies seem to be increasing with more number of fats foods, synthetic fabrics, pollutants in the air, etc.