Allergy Overview

Allergy is a hypersensitivity disease of the immune system. allergic reaction to normally harmless environmental substances known as allergens these reactions are acquired, predictable, and fast. Strictly, allergy is one of four forms of hypersensitivity and is called type I (or immediate) hypersensitivity. It 'is characterized by excessive activation of certain white blood cells called mast cells and basophils by a type of antibody known as IgE, an inflammatory reaction to the extreme. Common allergic reactions include rash, hives, hay fever, asthma attacks, allergies, and reactions to stinging insects, poisonous as wasps and bees.

Mild allergies like hay fever are very common in the human population and cause symptoms such as allergic conjunctivitis, itchy and runny nose. Allergies can play a role, such as asthma. In some people, severe allergies, environmental or dietary allergens or medications can cause fatal anaphylactic reaction.

A series of tests now exist to diagnose allergic diseases and includes tests of the skin for responses to known allergens or analyzing the blood for the presence and levels of IgE. Treatments for allergies include allergen avoidance, use of antihistamines, steroids or other oral medications, immunotherapy to desensitize the response to the allergen, and targeted therapy.