Allergy testing tomorrow afternoon, so must i stop all allergy meds today?

Meds/allergy testing: It depends on what type of tests. Allergy blood tests (rast, mast) are not affected and do not require stopping meds. If you are having skin testing, it is important to stop antihistamines and related drugs . Stopping shorter acting drugs for 24 hours is fine (e.g. Benadryl, (diphenhydramine) dimetapp, hydroxyzine) but 48-72 hours is better for longer-acting meds (zyrtec, xyzal, claritin, clarinex, allegra, etc.).

Yes: In reality, most allergy medications need to be stopped 48 to 72 hours before testing. This applies especially to antihistamine treatment. Some stomach medication, like ranitidine, famotidine, and Cimetidine also need to be held for 72 hours as they can interfere with testing too.