Description of Allergy
A state of hypersensitivity (or heightened or oversensitivity) in an affected individual to a particular substance, called the 'allergen'. This produces a characteristic response whenever the person is exposed to the allergen.
Persons most commonly affected by Allergy - Both sexes and all age groups.
Organ or part of body involved in Allergy
Various parts of the body depending on the nature of the allergy but including skin, respiratory system, joints and gastrointestinal system.
Symptoms and indications of Allergy
Symptoms usually develop rapidly, within a few minutes, and depend on the nature of the allergy. Common symptoms include nettle rash and skin reactions, swellings and puffiness, e.g. around eyes, wheezing and breathing difficulties, headaches, stomach pains, sickness and diarrhoea. Medical advice should be sought.
Treatment of Allergy
This depends upon the nature of the reaction but commonly involves the taking of antihistamine drugs. If the allergic response is more serious, as in an asthma attack, hospital treatment may be required, with the administration of bronchodilator and corticosteroid drugs by inhalation. If the allergic response is in the rare form of anaphylactic shock, prompt emergency treatment is necessary with the administration of adrenaline by means of an injection. This condition is fatal unless emergency treatment is promptly received.
Causes and risk factors of Allergy
In a nonallergic, unaffected person, antibodies present in the bloodstream destroy their particular allergens (antigens). However, in an allergic, affected person this reaction causes some cell damage and there is a release of substances such as histamine and bradykinin, which cause the reaction. Many substances, usually of a protein nature, can be allergens. The list includes many common foods, such as eggs, strawberries and shellfish, colorings and additives used in foods, plants and pollen, mites or dust from animals such as cats, dogs, horses and the feathers of birds. If the allergen is known then it may be possible for the individual to avoid exposure to it. Sometimes it is possible to decrease sensitivity to a particular allergen by gradually increasing exposure under careful medical supervision. However, a person may be allergic to a range of substances. In many people there may be a genetic element, with a family history of allergy.