Can antihistamines affect allergy testing?
Antihistamines like diphenhydramine, lortadine, fexofenadine, or azelastine nasal spray can potentially interfere with allergy testing. Skin reactivity may be suppressed from 28 hours to up to seven days if a patient is using antihistamines during allergy testing. Patients are advised to stop antihistamine use one week prior to testing. Let your doctor know all the medications you are currently using, including prescription and nonprescription, prior to testing.
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