An allergy is an abnormal reaction from an immune response to something that comes in contact of skin or inhaled, or ingested in body. Allergic reactions can lead to sneezing, wheezing, coughing, itching, skin rashes, swollen face or tongue, stomach pain, diarrhea etc.
Skin-testing is a method that doctors use to see whether a patient’s exposure to specific substances provokes an allergic response. Extracts (i.e. material used for allergy testing) are made from common allergens like various plant source (e.g. grass, trees, and pollen); mold spores; animal dander; cockroach or dust mite debris and certain foods.
Prick skin-testing is usually not painful but can cause some discomfort as the allergen is injected. It may also cause some itching for some time.
Depending on a particular patient’s history, anywhere from 10 to about 50 different allergens are tested.
After the allergen extracts are placed on the skin, doctor looks for signs of an allergic response. A positive response appears in the form of a raised bump or wheal, surrounded by a red area, or flare.
Usually, with a prick test, the raised area should be at least three millimeters to indicate a positive reaction. With an intradermal test, even larger reaction is required.
A positive test does not necessarily mean that you will have allergy symptoms when you are exposed to that allergen, or that the allergen is a cause of your symptoms. This is one reason why your skin test results need to be carefully correlated with your history by an experienced doctor or allergy specialist to determine appropriateness of results.
For proper allergy testing, all antihistaminic drugs (e.g. Tab Avil) should be stopped for five to seven days prior to skin-testing. You can continue to take any nasal steroid sprays and asthma medicines as per doctor’s advice.
Skin-testing is useful for anyone who wants or needs to identify specific allergy triggers. Anyone, regardless of age, can be skin tested for allergies.
The allergens which trigger allergy reaction during skin test can help doctor to educate you about how to avoid exposure to possible allergens. It can also help create a treatment plan to address your specific symptoms. For instance, if you are allergic to substances such as dust mites or pollen , you can take steps to limit your exposure to them.
Rarely patients may develop allergic reactions to skin-testing such as severe itching or wheezing, so testing should be performed in a facility capable of treating a reaction if it occur.
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