Allergy skin testing is a method to find out what you are allergic to. It is generally the best way to discover your allergies. Skin tests are done either by scratch/prick tests or intradermal tests. In scratch/prick tests, gentle pricks are made with disposable plastic prongs through drops of allergen extract on the skin of your back. In intradermal tests, small amounts of allergen extracts are injected into the skin of your upper arm.
If you are allergic, a slight swelling, itching and reddening of the skin will occur within 15 minutes after the tests are placed. Our staff will record the severity of the reaction. The allergic reaction from skin testing will generally subside after a short period of time. The information from the skin testing helps your doctor to determine the cause of your allergies.
Antihistamines and other medications with antihistamine-like effects will interfere with skin testing. Please stop taking the following medicines 2-7 days before skin testing:
Antihistamine tablets or liquids, with or without decongestants
Astelin, Astepro, Patanase nasal sprays or Dymista nasal sprays
Antidepressant medications called "tricyclic antidepressants"
Over the counter allergy medicines, cold or cough remedies
Over the counter sleeping aids, as they usually contain an antihistamine
To give specific examples, Benadryl needs to be stopped at least 2 days before skin testing; Astelin, Astepro, or Patanase 2 days, Zyrtec 2-5 days, Allegra 5 days, Claritin 7 days and Clarinex 7 days before skin testing. The required time off antihistamines may vary based on a patient's individual rate of metabolizing a medication.
Nasal sprays such as Atrovent, Flonase, Nasocort AQ, Nasonex, and Rhinocort Aqua, Veramyst, Omnaris do not contain antihistamine and may be taken up to the time of skin testing. The only nasal sprays that must be stopped before skin testing are Astelin, Astepro, and Patanase.
Inhaled medications for treating asthma such as albuterol, Xoponex, Flovent, Qvar, Pulmicort, Advair, Symbicort, and Dulera as well as oral tablets prednisone and Singulair do not contain antihistamine and may be taken up to the time of skin testing.
If you have a question about which medications need to be stopped, and for how long they should be stopped before skin testing, please call our friendly staff at 408-286-1707.