Yes, you can do the test. The problem is that you would not be able to take antihistamines for 5 - 7 days before the test depending on your allergist's directions. Antihistamines of any kind can give false results. So, if you do have the test make sure that you are very clear on what to avoid. Many people are not aware that PM pain meds like Tylenol PM have benadryl in them and have to be avoided as well.
Take care and feel better.
Hi, welcome to the forum, I quiet agree with bsml, you should go for the test during your allergic manifestations. This will help to find the agents you are allergic to. Along with avoidance of the allergy medications like anti histamines, you also need to discontinue gastric acid inhibiting drugs like ranitidine.
I suggest you to consult allergy specialist and follow the given instructions. Take care and regards.
Dr. Rajput brings up a good point. Many doctors do require their patients to go off H2 blockers (a specific type of antihistamine. H2 blockers inclue Zantac (ranitidine) and Pepcid. I cannot recall the chemical in Pepcid at the moment. Another questionable med is Elavil (amitriptyline). It is an antidepressant but has some antihistamine qualities.
Every doctor is different on these meds. Many don't want to cause issues with going off of these meds. They have very slight effects on testing, so many doctors will say to stay on them. It is best to ask your doctor about these meds.