I am allergic to everything (or so it seems). Sounds like an allergic reaction to something in the drug. Remember, there are other chemicals in the drug in addition to the 'active' drug and you might even be allergic to the chemical of the drug itself. It's hard to pinpoint allergies specifically, they're tricky but I wouldn't take a chance on anastrazole again. There are other options. You might be able to look up anastrazole and find all of the ingredients (both brand name and generic) and trace it back to certain ingredients that don't agree with you.
I had many symptoms from the two aromatase drugs I tired and had to quit. I also developed a skin rash that persisted for 18 months and has just now subsided. The rash could have been induced by the drugs (or others used during surgery) or it could be a type of lymphoma. I am watching and waiting on that. So, I wouldn't rule out an allergic reaction or intolerance.

This isn’t directly related to anastrozole, but I developed hives during chemo. The doc had me take Zantac! I knew it just for stomach issues but it’s actually a type of antihistamine. Maybe you knew that already.

thanks! I will keep that in mind. I was using the walgreens version of Benadryl. anything helps!

Oilermama -- Just jumping in with my two cents here on the subject of Benadryl. It is an anticholinergic drug which does have side effects (especially as we age). What got my attention last year was a Harvard Research paper entitled "Common Anticholinergic Drugs Like Benadryl Linked to Increased Dementia Risk." The paper is online and you might want to give it a read. The older I get, the more concerned I've become regarding the effects of prescription and over-the-counter drugs, promoted by the pharmaceutical industry and not studied well by our own Food and Drug agency before its approval.