: Facilities : Skin Allergy Test
Skin allergy testing is a method for medical diagnosis of allergies that attempts to provoke a small, controlled, allergic response.
A microscopic amount of an allergen is introduced to a patient's skin by various means:
- Prick test or scratch test: pricking the skin with a needle or pin containing a small amount of the allergen.
- Patch test: applying a patch to the skin, where the patch contains the allergen
If an immuno-response is seen in the form of a rash, urticaria (hives), or (worse) anaphylaxis it can be concluded that the patient has a hypersensitivity (or allergy) to that allergen. Further testing can be done to identify the particular allergen.
Some allergies are identified in a few minutes but others may take several days. In all cases where the test is positive, the skin will become raised, red and appear itchy.
Skin end point titration
There are no major preparations required for skin testing. At the first consult, the subject's medical history is obtained and physical examination is performed. All consumers should bring a list of their medications because some may interfere with the testing. Other medications may increase the chance of a severe allergic reaction. Medications that commonly interfere with skin testing include the following:
- Histamine antagonists like Allegra, Claritin, Benadryl, Zyrtec
- Antidepressants like Amitriptyline, Doxepin
- Antacid like Tagamet or Zantac
Consumers who undergo skin testing should know that anaphylaxis can occur anytime. So if any of the following symptoms are experienced, a physician consultation is recommended immediately:
- Low grade Fever
- Lightheadedness or dizziness
- Wheezing or Shortness of breath
- Extensive skin rash
- Swelling of face, lips or mouth
- Difficulty swallowing or speaking
Even though skin testing may sound like a benign procedure it does have some risks which include swollen red bumps (hives) may occur after the test. The hives usually disappear in a few hours after the test. In rare cases they can persist for a day or two. These hives may be itchy and are best treated by applying an over the counter hydrocortisone cream.
Skin testing can be done on individual of all ages. However, there are times when a skin test should not be done. Individuals who take medications for depression, gastric acidity or antihistamines should not undergo this test.
There are some individuals who are highly sensitive to even the smallest amount of allergen and in such scenarios, allergic testing is not recommended. Whenever the chances of an anaphylactic shock are high, the test is best avoided.
At PH Medical, we perform screening test for over 100 different allergens. Click here to see the complete list.