ALLERGIES

What is an allergy? An allergy, or more appropriately, an allergic response happens when our bodies produce excess amounts of a specific antibody called Immunoglobulin E (IgE). Our bodies immune system helps keep us healthy by producing disease fighting antibodies. These antibodies are capable of destroying harmful foreign substances like viruses and bacteria that causes disease. In people with allergies, these antibodies are overstimulated and react to normally harmless substances. Substances that can cause allergic reactions are called allergens. When people with allergies are exposed to them, the body launches a full-scale attack by producing large amounts of IgE. It is the IgE antibody that cause the majority of allergic reactions.

How common are allergies? More than nine million Canadians suffer from some form of allergy. Many allergies can happen at any age, and can go and come at any time throughout our lives. Children with allergic parents are more likely to develop allergies, but not necessarily the same allergies that their parents have.

Common allergens are pollens, mould spores, dust mites, animal dander, certain foods, medicines and insect stings. Factors that can heighten an allergic response, but are not considered allergens include weather conditions such as sunlight, humidity, heat or cold; and irritants such as cigarette smoke, paint fumes, solvents and perfumes.

Allergic symptoms are triggered when our bodies come into contact with the allergen, through the air we breathe, the foods we eat, and the things we touch. As a result, allergic reactions may occur in any part of the body.

Commonly affected areas:

• Eyes - itching, redness, and tearing may signal allergic conjunctivitis. Dark circles that form under the eyes are telltale signs of allergies known as "Allergic shiners".
• Nose - itchy, runny, stuffy nose and excessive sneezing are symptoms of allergic rhinitis or "Hayfever".
• Lungs - shortness of breath, wheezing and chest tightness are symptoms of asthma.
• Digestive tract - stomach cramps, bloating, vomiting and diarrhea may result from food allergies.
• Skin - allergic reactions to food, medicines, household chemicals, plants or insect stings may cause itchy rashes or patches of swelling or red blotches known as hives.

How quickly do allergy attacks happen? Allergy attacks may occur immediately after exposure to an allergen or several days later. An allergic reaction can range in severity from mild to a life threatening medical emergency (anaphylaxis). It is important to know what is causing your allergies.

Diagnosis of allergies. Allergies may be diagnosed by your physician, through a physical examination and a detailed history of your symptoms and living habits. Two types of tests may be used to confirm their diagnosis.

• Skin test is the most commonly used test. Suspected allergens are applied directly to the skin, usually the back, with a skin prick device, or a needle. The appearance of a raised area or welt would indicate a sensitivity to the allergen applied. The size of the welt may indicate the severity of the reaction. The skin test is less effective in infants and adults older than sixty years. Some medications may influence the results by giving a false negative.
• Blood test using ImmunoCAP technology, a small blood sample is analyzed in the laboratory and determines the precise amount of IgE antibodies for each specific allergen present in the blood. The blood test using the ImmunoCAP is not affected by medications, specifically antihistamines. A single blood sample may be used to test for a number of different allergens at the same time. Over 500 allergens can be tested with unprecidented accuracy.

Controlling your allergies. The best way to control an allergy is to avoid the allergen. If this is impossible, the next best thing would be to limit exposure to the allergen, and treat the symptoms. Mild symptoms can be controlled with over-the-counter medications, such as antihistamines and decongestants. People with severe allergic reactions may need to carry an "EpiPen", a needle that delivers a dose of epinephrine, to counter an anaphylactic reaction.

Sometimes, if your are at risk of developing a life-threatening reaction to a particular allergen, your physician may prescribe immunotherapy, or "allergy shots".

Click to read an article on the Scientific Principles of an Allergic Reaction.

Links
www.isitallergy.com
www.diagnostics.nu