IMMUNOLOGY

Detailed explanation-1: -Overview. Allergies occur when your immune system reacts to a foreign substance-such as pollen, bee venom or pet dander-or a food that doesn’t cause a reaction in most people. Your immune system produces substances known as antibodies.

Detailed explanation-2: -Allergic reactions start in your immune system. If you are allergic to a substance such as dust, mold, or pollen and you come into contact with it, your immune system may overreact. It may make antibodies that attack the substance.

Detailed explanation-3: -Allergic reactions (hypersensitivity reactions) are inappropriate responses of the immune system to a normally harmless substance. Usually, allergies cause sneezing, watery and itchy eyes, a runny nose, itchy skin, and rash.

Detailed explanation-4: -An allergic reaction is a set of symptoms that the body develops in response to a foreign substance. An allergic reaction occurs when the body becomes hypersensitive to a substance, such as a drug, dust, or pollen. The reaction can be localized, in an isolated place in the body, or wide spread.

Detailed explanation-5: -When a harmless substance such as dust, mold, or pollen is encountered by a person who is allergic to that substance, the immune system may over react by producing antibodies that “attack” the allergen. The can cause wheezing, itching, runny nose, watery or itchy eyes, and other symptoms.

Detailed explanation-6: -An allergic reaction is an overreaction of the immune system to a substance called an allergen. Allergens include chemicals, foods, medicines, mould, plants, and pollen.