The word \u2018allergy\u2019 means an altered or abnormal tissue reaction after exposure to a foreign antigen. An allergic reaction may occur when there is contract between a foreign protein – an allergen – and body tissues that are sensitive to it.<\/p>\n
The allergens may reach the tissuesby direct contact with the skin or mucous membranes, or through the blood stream after absorption.<\/p>\n
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Allergic reactions may occur within a few minutes of the patient coming in contact with the allergen or they may be delayed for several hours or even several days. Almost any part of the body can be affected by allergies.<\/p>\n
The portion of the body which is affected is called a shock organ. Common sites are nose and eyes, the skin, chest, intestines, and ears.<\/p>\n
Allergic reactions are caused by a wide range of substances and conditions. These include pollen, dust, cosmetics, and animal hair; poisonous plants, serums, vaccines and drugs; physical agents such as heat, cold and sunlight; as well as a variety of foods.<\/p>\n