Define allergy and give different classes of allergy
Answers
hi
Allergy: A misguided reaction to foreign substances by the immune system, the body system of defense against foreign invaders, particularly pathogens (the agents of infection). The allergic reaction is misguided in that these foreign substances are usually harmless. The substances that trigger allergy are called allergen. Examples include pollens, dust mite, molds, danders, and certain foods. People prone to allergies are said to be allergic or atopic.
Although allergies can develop at any age, the risk of developing allergies is genetic. It is related to ones family history of allergy. If neither parent is allergic, the chance for allergies is about 15%. If one parent is allergic, the risk increases to 30% and if both are allergic, the risk is greater than 60%.
Allergens cause the production of immunoglobulin E (IgE), an antibody that all of us have in small amounts. Allergic persons, however, produce IgE in abnormally quantities. Normally, this antibody is important in protecting us from parasites, but not from other allergens. During the sensitization period in allergy, IgE is overproduced. It coats certain potentially explosive cells that contain chemicals including histamine. These chemicals, in turn, cause inflammation and the typical allergic symptoms. This is how the immune system becomes misguided and primed to cause an allergic reaction when stimulated by an allergen.
The most common allergic conditions include hay fever (allergic rhinitis), asthma, allergic eyes (allergic conjunctivitis), allergic eczema, hives (urticaria), and allergic shock (also called anaphylaxis and anaphylactic shock). For a thumbnail sketch of each of these conditions:
Hay fever (allergic rhinitis) is the most common of the allergic diseases and refers to seasonal nasal symptoms that are due to pollens. Year round or perennial allergic rhinitis is usually due to indoor allergens, such as dust mites or molds. Symptoms result from the inflammation of the tissues that line the inside of the nose (mucus lining or membranes) after allergens are inhaled. Adjacent areas, such as the ears, sinuses, and throat can also be involved. The most common symptoms include:
Runny nose
Stuffy nose
Sneezing
Nasal itching (rubbing)
Itchy ears and throat
Post nasal drip (throat clearing)
Learn the signs and symptoms of food allergy. Discover treatment options and avoidance tips through ACAAI.
Skin Allergy
Learn about allergic skin reactions and what causes them.
Dust Allergy
People who have dust allergies are familiar with sneezing—but sneezing isn’t the only uncomfortable symptom.
Insect Sting Allergy
Learn the signs and symptoms of different types of insect sting allergy. Discover treatment options through ACAAI.
Pet Allergy
Pet allergies can contribute to constant allergy symptoms, such as causing your eyes to water, or causing you to start sneezing.
Eye Allergy
Learn about eye allergies, a condition that affects millions of Americans.
Drug Allergies
If you develop a rash, hives or difficulty breathing after taking certain medications, you may have a drug allergy.
Allergic Rhinitis
If you sneeze a lot, if your nose is often runny or stuffy, or if your eyes, mouth or skin often feels itchy, you may have allergic rhinitis.
Latex Allergy
Allergic reactions to latex may be serious and can very rarely be fatal. If you have latex allergy you should limit or avoid future exposure to latex products.
Mold Allergy
Learn the signs and symptoms of mold allergy. Discover treatment options and avoidance tips through ACAAI.
Sinus Infection
Sinus infection is a major health problem. It afflicts 31 million people in the United States.
Cockroach Allergy
Learn the signs and symptoms of cockroach allergy. Discover treatment options and preventive cleaning tips through ACAAI.
hope it helps (:
Allergy occurs when something reacts to a human being and leads to many skin problems.
Different types of allergy are as follows:-
1. Food Allergy
2. Skin Allergy
3. Dust Allergy
4. Insect Sting Allergy
5. Pet Allergy
6. Eye Allergy
7. Allergic Rhinitis
8. Mold Allergy
9. Latex Allergy
10. Sinus Infection
11. Cockroach Allergy