Allergy Skin Testing

Allergy skin testing will determine what airborne particles are the culprit of your symptoms.  The skin test panel consists of tree pollens, grass pollens, weed pollens and mold spores, common in Central Texas, plus dust mites, cat, and dog dander.  The skin testing is completed in two stages, with an initial state of prick or scratch testing, which is performed on your back with a small plastic needle.  The second phase consists of superficial injections with a small syringe on your arms, which is only performed if your initial scratch test is negative to a particular substance.  It is a good idea to wear a short sleeve shirt when you come for your skin testing.  Each phase of the testing takes approximately 30 minutes.  A positive reaction is a small area of itching and redness, smaller than a mosquito bite, which resolves in 15 - 20 minutes.  Food skin tests are not part of the skin test panel, but can be performed separately if your history suggests a food allergy.  Occasionally, your skin tests may be completely negative, indicating you have primarily chronic sinusitis or chronic nasal problems on a non-allergic basis.  Below are some medications that my interfere with your skin tests.  Guidelines are provided below to assist with completion of your skin tests.

• Please avoid all antihistamines 3 days prior to your skin tests.  Zyrtec^® and Clarinex^® should be avoided for 5 days prior to skin testing.  Antihistamines are present in multiple cold, cough, sinus and allergy  medications.  Some common over-the-counter medications that contain antihistamines include Comtrex^®, Benadryl^®, Dimetapp^®, Tavist^®, Triaminic^®, Alka-Seltzer^® Plus Cold, Claritin^®, and many others that are not mentioned here.  Prescription antihistamines that should also be discontinued include Allegra^®, Semprex^®, Rynatan^® and Actifed^®.  Please discontinue all of these at least 3 - 5 days prior to your skin tests appointment, and if you have questions about medications interfering with your skin tests, please call the clinic.
  
  

• Most over-the-counter sleep aids contain antihistamines and should also be stopped 3 days before skin testing.  Examples include Nytol^®, Bayer^® PM, Tylenol^® PM, Unisom^®, Sominex^®, and several others.
  
  

• Other medications that are not classified as antihistamines also may inhibit your skin tests.  Tagamet^® (cimetidine), Zantac^® (rantidine), Elavil^® (amtitripyline) should be discontinued 3 days prior to your tests.  Please discuss alternatives for these medications if warranted with your primary care physician.
  
  

• Certain medications such as beta blockers that are used to treat hypertension and irregular heart beats, cannot be taken during skin testing.  Beta blocker medications such as Lopressor^®, atenolol, and Tenormin^®, should be stopped at least the day of your skin tests.  Please discuss your beta blocker medication with your allergist before stopping it.
  
  

• You can continue your asthma medications to include your inhalers, and you can continue your nasal spray, with the exception of Astelin^®, which needs to be stopped one week prior to your tests.

At the completion of your testing, your allergist will discuss with you the results of your skin tests.  He will discuss treatment options of allergy shots, allergen avoidance, or continued medical therapy.  A copy of your skin test results will be given to you for your information.  On your skin test sheet, you should react to histamine, the positive control, which is a test to verify that your skin reacts normally.  Also, a positive test to the mold spore Penicillum does not mean you are allergic to the antibiotic penicillin.  Your allergist can answer any further questions regarding the results of your skin tests.