Allergy an acquired, abrmal reaction, such as running se, rash, or breathing difficulty, in persons sensitive to certain substances (allergens) that do t rmally cause a reaction. The allergy-producing substances or allergens are all around us. Animal dander, pollen produced by different trees and flowers, house dust, etc, are examples of common allergens; but there may be an endless list of allergens, many of which are seemingly incent substances. Allergic conditions include eczema, allergic rhinitis or coryza, hay fever, bronchial asthma, urticaria, and food allergy. Allergens may be introduced by contact, ingestion (eg, food), inhalation (eg, pollen), or injection (eg, drugs).
Pollen belongs to the class of allergens kwn as inhalents because they are breathed into the respiratory tract. Other allergens in this group are the airborne, free-floating spores of fungus, house dust, animal dander, and cosmetics. Foods are a frequent source of trouble. To many people the common food items that produce an allergic reaction are milk, egg, prawn and shrimp, wheat, some type of fish, beef, etc. The potential allergens such as furs, leather, plants, flowers, dyes, cosmetics, industrial chemicals, and insecticides may cause inflamation of the skin. The bronchial asthma and some types of eczema are in fact due to allergic reactions.
In Bangladesh most sensitive persons are sensitive t just to one substance but to a number of them. Allergies are among the commonest of disorders; surveys have shown that at least 10 percent of the population suffers from them in either acute or chronic form. Heredity appears to play a part in many cases of allergy. If there is an allergic person in a family, there is a greater chance that his or her children will show a similar allergy. Emotional factors may also contribute to some allergies.
Records of allergy patients in different hospitals of Bangladesh indicate that allergies can show up at any stage of life, from childhood to old age. Severity often depends upon how much of the allergent the patient is exposed to and for how long. Some persons, even those with severe allergies, lose their sensitivities and recover spontaneously. Many individuals lose their allergic tendencies as they grow old.
For numerous allergies, medications provide relief. Antihistamines have wide effectiveness although they are t successful in all cases. The best way to get rid of allergic reactions is to identify the substance provoking the disorder and avoid it. If it is animal dander, the pet responsible will have to depart.
When the cause is a food, drug, or article of clothing, it must be avoided at all costs. In case of dust allergy, the house must be vacuum-cleaned or wiped with wet cloth regularly. [SM Humayun Kabir]
Pollen allergen The fertilizing element of flowering plants produced by the male sexual organ may induce allergy. Pollens are fine, powdery, yellowish grains or spores, and sometimes remain in masses. Many airborne pollen types are considered to be the major component of allergens. They cause widespread upper respiratory tract and naso-bronchial allergy with manifestations like seasonal rhinitis, asthma, hay fever, and various types of bronchial troubles. The magnitude of incidence of an area depends on the genetic constituents of the population, meteorological influence and type of the availability of allergenic pollen plants. It is estimated that 10-35% of the population suffers from allergenic diseases at one time or the other. Pollen grains of grasses and conifers are the principal group of allergen producers in the world. In Bangladesh the incidence of allergen pollen is high. The important allergenic pollen grains are released by plants such as Lantana camara, Acacia species, Cassia fistula, Cocos nucifera, Eleusine indica, Datura metel, Amaranthus spisus, Cydon dactylon, Achyranthes aspera, Albizzia lebbeck, Brassica campestris, Cannabis sativa, Carica papaya, Mangifera indica, and Xanthium stramarium. [Mostafa Kamal Pasha]