Patient Instruction for Allergy Skin Testing
Skin Test:
Skin tests are methods of testing for allergic antibodies. A test consists of introducing small amounts of the suspected substance, or allergen, into the skin and noting the development of a positive reaction (which consists of a wheal, swelling, or flare in the surrounding area of redness). The results are read at 15 to 20 minutes after the application of the allergen. The skin test methods are:
Prick Method:
The skin is pricked with a needle where a drop of allergen has already been placed.
Intradermal Method:
This method consists of injecting small amounts of an allergen into the superficial layers of the skin.
Interpreting the clinical significance of skin tests requires skillful correlation of the test results with the patient’s clinical history. Positive tests indicate the presence of allergic antibodies and are not necessarily correlated with clinical symptoms.
You will be tested to important (location) airborne allergens and possibly some foods. These include, trees, grasses, weeds, molds, dust mites, and animal danders and, possibly some foods. Prick (also known as percutaneous) tests are usually performed on your arms or back. Intradermal skin tests may be performed if the prick skin tests are negative and are performed on your arms. If you have a specific allergic sensitivity to one of the allergens, a red, raised, itchy bump (caused by histamine release into the skin) will appear on your skin within 15 to 20 minutes. These positive reactions will gradually disappear over a period of 30 to 60 minutes, and, typically, no treatment is necessary for this itchiness. Occasionally local swelling at a test site will begin 4 to 8 hours after the skin tests are applied, particularly at sites of intradermal testing. These reactions are not serious and will disappear over the next week or so. They should be measured and reported to your physician at your next visit. You may be scheduled for skin testing to antibiotics, caines, venoms, or other biological agents. The same guidelines apply.
PRECAUTIONS
No prescription or over the counter oral antihistamines should be used 4 to 5 days prior to scheduled skin testing. These include cold, cough and sinus medications, hay fever medications, or oral treatments for itchy skin, over the counter allergy medications, such as Claritin, Zyrtec, Allegra, Actifed, Dimetapp, Benadryl, hydroxyzine (Atarax), and many others. Prescription antihistamines such as Clarinex and Xyzol should also be stopped at least 5 days prior to testing. If you have any questions whether or not you are using an antihistamine, please ask the nurse or the doctor. In some instances a longer period of time off these medications may be necessary.
You should discontinue your nasal and eye antihistamine medications, such as Patanase, Pataday, Astepro, Optivar, or Astelin up to 5 days before the testing. In some instances a longer period of time off these medications may be necessary. If you have any questions whether or not you are using an antihistamine, please ask the nurse or the doctor. In some instances a longer period of time off these medications may be necessary.
Medications such as over the counter sleeping medications (e.g. Tylenol PM) and other prescribed drugs, such as amytriptyline hydrochloride (Elavil), doxepin (Sinequan), and imipramine (Tofranil) have antihistaminic activity and should be discontinued at least 2 weeks prior to receiving skin test after consultation with your physician. Please make the doctor or nurse aware of the fact that you are taking these medications so that you may be advised as to how long prior to testing you should stop taking them. If you are taking antidepressants, psychotropic or anitreflux medications, they may have antihistaminic properties and should be discussed with the doctor prior to testing.
YOU MAY
You may continue to use your intranasal allergy sprays such as Flonase Rhinocort, Nasonex, Nasacort, Omnaris, Veramyst and Nasarel.
Asthma inhalers (inhaled steroids and bronchodilators) and oral theophylline (Theo-Dur, T-Phyl, Uniphyl, Theo-24, etc.) do not interfere with skin testing and should be used as prescribed. Leukotriene antagonist s (e.g. Singulair, Accolate) should be held the night before testing.
Most drugs do not interfere with skin testing but make certain that your physician and nurse know about every drug you are taking (bring a list if necessary).
Skin testing will be administered at this medical facility with a medical physician or other health care professional present since occasional mild or very rare severe reactions may require immediate therapy. Talk to your doctor about any further details. Please let the physician and nurse know if you are pregnant or taking beta-blockers. Allergy skin testing may be postponed until after the pregnancy in the unlikely event of a reactions to the allergy testing and beta-blockers are medications they may make the treatment of the reaction to skin testing more difficult.
Please note that reactions rarely occur but in the event a reaction would occur, the staff is fully trained and emergency equipment is available.
After skin testing, you will consult with your physician or other health care professional who will make further recommendations regarding your treatment.