About Allergy Skin Test
This information is intended for general information only and should not be considered as medical advice on the part of Health-Tourism.com. Any decision on medical treatments, after-care or recovery should be done solely upon proper consultation and advice of a qualified physician.
What is an allergy?
An allergy is what occurs when you react to things like cat’s fur or pollen that don’t affect most people. An allergic reaction is what happens when you come into contact with something that you are allergic to (an allergen). Anaphylaxis occurs when an allergic reaction is very severe.Symptoms of an allergic reaction
What is an allergy skin test?
- Symptoms depend on what the patient is allergic to and how they come into contact with it.
- Itchy, runny or blocked nose
- Itchy, red watering eyes
- Wheezing, shortness of breath, chest tightness, and a cough
- Raised, itchy red rash (hives)
- Tummy pain, nausea, diarrhea and vomiting
- Dry, red cracked skin
This is a test conducted to investigate what you are allergic to and how the allergy is characterized. Usually, you are tested with 10-50 different allergens.
How is an allergy skin test done?
10-50 various allergens are placed on a part of your body in children, usually the back and in adults, it is on the forearm. After about 15 minutes the skin is observed for any red lumps. Your skin may itch where the allergens are placed.
The test is usually done in the doctor’s office. The test typically takes 20 -40 minutes. Some test results in immediate allergic reactions while others develop over a period of days.Types of allergy skin tests
Skin prick test
It is also known as a scratch or puncture test. This test checks for immediate allergic reactions to many different substances at once. The test is usually done to identify allergies to mold, dust mites, pollen, pet dander, and foods.
The test is not painful and there is no bleeding but it may cause some discomfort. The needles barely penetrate the skin. The test site is cleaned with alcohol. The nurse draws small marks on your skin and a drop of allergen extract is applied next to each mark. A lancet is then used to prick the extracts into the skin surface. A new lancet is used for each allergen.
After cleaning the test site with alcohol, the nurse draws tiny marks on your skin, and then he/she applies a drop of allergen extract next to each mark. He or she then uses a lancet to pierce/prick the extracts into the skin's surface. A new lancet is used for each allergen. To see if your skin is having normal reactions two more substances are scratched into your skin’s surface:
- Histamine: This substance causes a skin response in most people. If there is no reaction then you allergy skin test may not reveal an allergy even if one is present.
- Saline or glycerine: Most people do not react to these substances. If you do then it may be an indication of very sensitive skin. The results will have to be cautiously interpreted to avoid false allergy diagnosis.
15 minutes after the skin pricks the nurse will observe your skin for any signs of allergic reactions. A red, itchy bump develops on areas with substances that cause allergic reactions. The nurse will measure the bumps size.
Skin injection test
This is an intradermal test that injects a small allergen extract into the skin of your arm. This test may be recommended to check for allergies to penicillin or insect venom.
How should I prepare for the test?
- Patch test: This test is usually done to test for contact dermatitis. A patch test is useful for detecting delayed allergic reactions which can develop after several days. Patch tests do not use needles. 20-30 allergen extracts including, fragrances, latex, metals, and resins are applied on patches which are then placed on your skin. The patches are worn for 2 days. Bathing and activities that cause heavy sweating should be avoided during this time. The patches are removed at your doctor’s office. Irritated sites indicated an allergy.
Inform your doctor of all medicines that you are taking.
You should not take antihistamines for 3-7 days before the test. Ask your doctor when to stop taking them.
Learn more about Allergy Skin Test