Allergy Testing

Skin Tests

Skin allergy testing is the most sensitive and accurate way to diagnose the cause of allergies. Skin tests are accurate for sensitivity to pollens, molds, pet dander, dust, feathers, cockroach, foods and the venoms of stinging insects like wasps and fire ants.

Solutions extracted in a laboratory from an allergen (a substance which may cause an allergic reaction) is pricked or injected into the skin. Reactions occur within 15 minutes. Itching, redness, and swelling at the skin test site indicate a positive reaction.

Using the procedures in our office most people do not find allergy skin testing painful. We are usually able to test even young children without significant discomfort.

 

Prick Skin Tests

These tests may be performed on the back or forearm. The area is cleaned with alcohol and marks are made on the skin with a pen to identify the various allergens. A small plastic device with a  point is dipped into an allergen solution and used to make a tiny prick of the skin. A separate prick is made for each allergen. Swelling and redness at each prick site is measured in 15 minutes.  Most people say the prick test feels like getting touched with the point of a pencil or a fingernail. 

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Blue plastic prick testing device above, reactions to allergens below.

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Intradermal Skin Tests

If a prick test is negative to a particular allergen, more sensitive intradermal testing is done. A small amount of allergen extract is injected with a tiny needle under the skin of the upper arm. Swelling and redness is measured in 15 minutes.

We usually apply an anti-itch spray to the site of any positive reactions which immediately lessens itching. Skin test reactions usually fade away within one to two hours. Most people feel fine after skin tests, and can return to work or school.

Results:

Immediately after skin tests are completed you will meet with your physician (Dr. Howland or Dr. Lieberman) to discuss the results and treatment plan. You will be provided with a sheet showing your test results. Skin testing and discussion of your results usually takes  1½ to 2 hours.


MEDICATIONS THAT INTERFERE WITH ALLERGY SKIN TESTING

These medications interfere with allergy skin tests and SHOULD BE DISCONTINUED PRIOR TO TESTING:

  • Antihistamines:
    • 3 days prior to testing stop most over the counter allergy, cold and sleep medications (Benadryl, Clortrimeton, diphenhydramine, etc.), and many prescription antihistamines (Allegra, Allerx, Astelin and Patanase nasal spray, fexofenadine, etc.) .
    • 5 days prior to skin testing stop Alavert, Claritin, Clarinex, loratadine, Xyzal, Zyrtec, Atarax (hydroxyzine) and doxepin.
     
  • Antidepressants:
    • Older antidepressants like Elavil (amitryptyline) should be stopped 3 days prior to testing.
    • Newer antidepressants (Prozac, Zoloft, etc.) do not interfere with testing.
     

Most medications do not interfere with skin testing, and may be continued.


 DO NOT STOP:

  • Cortisone nasal sprays (fluticasone, Nasonex, Nasacort AQ, Rhinocort, Veramyst, etc.)
  • Asthma medications (Albuterol, Flovent, Singulair, Advair, etc.)
  • Antibiotics
  • Eye drops for allergy (Patanol, Elestat, Zaditor, etc.)
  • Decongestants (Sudafed, Sudafed PE, etc.)
  • Oral steroids (Prednisone, Medrol, Prelone, etc.)
  • Medicines for other conditions such as diabetes, arthritis, reflux, high blood pressure, birth control pills, etc.

PATIENTS WHO SHOULD NOT BE ALLERGY SKIN TESTED

  • Women should not be skin tested if they are or may be pregnant.
  • Patients taking beta blocker medications on a daily basis should not be skin tested or take allergy shots.

 

The use of beta blocker medications (which may be prescribed for high blood pressure, heart conditions, glaucoma, migraine prevention, etc.) may hinder the effectiveness of treating systemic reactions to allergy skin testing or immunotherapy. Below is a partial list of the currently available beta blocker medications.  Please make sure you are not taking one of these medications if you are scheduled for skin testing. Ask your pharmacist, prescribing physician or one of our nurses if you are not sure if your medication is a beta blocker.

 

BETA BLOCKERS:

Betapace Tablets  (Sotalol)

Blocadren Tablets  (Timolol)

BreviblocInjection  (Esmolol)                                        

Bystolic (nebivolol)

Cartrol Filmtab Tablets  (Carteolol)

Coreg Tablets (Carvedilol)

CorgardTablets  (Nadolol)

Inderal-LA Capsules  (Propranolol)

Inderal Tablets  (Propranolol)

Lopressor (Metoprolol)

Kerlone Tablets  (Betaxolol)

Levatol Tablets  (Penbutolol)

Normodyne, Trandate (labetolol)

Trasicor (oxprenolol)

Sectral Capsules  (Acebutolol)

Tenormin Tablets / Injectable  (Atenolol)

Toprol-XL Tablets  (Metoprolol)

Visken (pindolol)

Zebeta Tablets  (Bisoprolol)

InnoPran XL Capsules  (Propranolol)

 

BETA BLOCKERS WITH DIURETICS:

Corzide 40/5 Tablets  (Nadolol)

Corzide 80/5 Tablets  (Nadolol)

Inderide LA Capsules  (Propranolol)

Lopressor HCT (Metoprolol)

Tenoretic Tablets  (Atenolol)

Timolide Tablets  (Timolol)

Ziac Tablets  (Bisoprolol)

Inderide Tablets  (Propranolol)

 

BETA BLOCKER EYE DROPS:

Betimol Ophthalmic Solution (Timolol)

  

Betagan (levobunolol)

Betoptic S Ophthalmic Suspension  (Betaxolol)

  

Cosopt Sterile Ophthalmic Solution  (Timolol)

 

Ocupress (carteolol)   

Timoptic in Ocudose  (Timolol)

Timoptic Sterile Ophthalmic Solution  (Timolol)

Timoptic-XE Sterile Ophthalmic Gel  (Timolol)

                                                 



Blood Tests

Allergy blood tests can also be used to detect sensitivities. Blood allergy testing is most often done when a patient has extensive skin problems preventing skin allergy testing, or when a patient can not stop a medicine (such as a beta blocker) which may interfere with skin tests.  Blood allergy tests may also be helpful for food allergy.

Blood allergy testing is generally more expensive and less sensitive than skin allergy testing and fewer allergens are available for blood testing. Usually, only one tube of blood is needed to do 30 or more tests. Test results are available in 1-2 weeks.