Very little information about allergy

Allergies are an overreaction of the body's immune system to specific substances that it misidentifies as harmful. This overreaction of the body's immune system is known as an allergic reaction and the substances that cause it are called allergens. Potential allergens can be anything from dust mites and pollen to insect stings, fragrances, and foods such as shellfish and peanuts. Whatever the allergen, allergic reaction symptoms can be miserable, ranging from a runny nose and watery eyes to breathing problems, diarrhea, hives, and even death.

The Allergy Chain of Events The allergen enters your body where it is misidentified as a harmful and foreign substance by the specialized white blood cells that work together to identify and exterminate bacteria and viruses (B-cells and T-cells). The body then begins producing IgE antibodies which are proteins specifically engineered to neutralize the threat of the mis-identified allergen. These IgE antibodies attach themselves to a specialized blood cell - mast cell - and lie in wait for the same substance to enter the body again.

The Allergy Chain of Events When the allergy sufferer comes into contact again with the same allergen, the IgE antibodies begin breaking down the mast cells. As mast cell walls are destroyed, each releases a load of chemicals, including histamine, prostaglandins, and leukotrienes, into the surrounding tissues and blood. These chemicals then bind to receptors in the blood, nasal tissues and other tissues, causing a host of symptoms ranging from swelling to sneezing and a runny nose to hives. The release of histamine is what causes a cascade of allergy symptoms that can affect the GI tract, skin, respiratory system or cardiovascular system.

Clinical History Physical Exam Diagnostic tests Blood tests Lung x-rays Pulmonary function tests Cultures to detect infection Allergy Diary When you suffer allergies - At a certain time a day, or during a particular season? Allergy triggers - Do you get symptoms after touching a pet or after eating a certain food? Allergy symptoms - What symptoms do you suffer when you're having an allergic reaction?

Types of Allergy Tests Skin Tests When: If we suspect that the allergies are caused by airborne allergens (substances like dust and pollen), or from contact allergens (allergens that touch your skin such as nickel, dyes or fragrances). Skin tests are less expensive and are generally more accurate than blood tests for allergies. Blood Tests When: If there is some reason why we cannot take a skin test, such as for a patient who is extremely sensitive to a particular allergen. Elimination or Food Challenge Tests When: If we suspect food allergies.

Skin Tests Scratch or Prick Tests Patch Tests Intradermal Tests

Scratch or Prick Tests Scratch tests are the most common of all. We place drops of suspected allergens on the arm or back, marking each with a pen to identify the allergen. Then gently scratche or pricks the skin through the drops, allowing allergens to penetrate. After about 15 to 30 minutes we will check for any reaction (such as redness or itching).

Patch Tests We paint a small amount of a suspected allergen onto a healthy patch of skin, or paints the allergen onto a pad and places it on the skin. The skin is covered for up to 2 days, after which we check for any reaction.

Intradermal Tests We will inject a tiny amount of a suspected allergen under the skin using a very fine needle. Intradermal tests are less common than scratch, prick or patch tests but they are also more accurate and may be done as a follow-up to these tests.

Potential Risks and Drawbacks of Skin Tests Fever Dizziness or lightheadedness Wheezing Inability to breathe or shortness of breath

Blood Tests RAST Test: lab will look for the IgE antibodies that show an allergic reaction has taken place. Both skin tests and blood tests are about 90% accurate. Therefore, we will usually perform the simpler skin tests unless a patient is afraid of the needles used for the scratch/prick test, is in danger of an anaphylactic reaction, or has some skin problems (such as an all-over rash) that make skin tests difficult to perform.

Elimination or Food Challenge Tests Elimination Tests Food Challenge Tests

Elimination Tests Suspected food allergies are eliminated from the diet for two or three weeks. Patients keep a food diary and a doctor supervises their diet to ensure proper nutrition. Both doctor and patient watch for allergy symptoms and check if they diminish in the absence of the suspected food allergen. After following the diet, we will instruct patient to re- introduce the suspected allergen into his diet, and to watch carefully for symptoms.

Food Challenge Tests A sample of a suspected food allergen is given to the patient. Both doctor and patient monitor any reactions.