Well, I had high hopes after abstaining for a few months, but unfortunately I am still experiencing a similar reaction. Took diphenhydramine (Benadryl) 1 hour prior to ingesting any kava, used extract only (and a small amount, at that) to avoid ingesting cellulose/fiber, and woke up with a red face and hives on my neck and upper chest.
I'm not trying to scare anyone, but rather to offer my experiences for the benefit of all kava users and kava research. If anyone knows of someone who is doing research on kava, I'm happy to contribute my experiences, which as far as I can tell, seem to be pretty unique.
The one difference I noticed between taking Benadryl PRIOR to kava was that I was not as itchy as I was on previous occasions when I took antihistamines AFTER the fact, and I lacked the extreme sunburnt feeling. Sure, my face is red and feels warm, but I can comb my hair without bringing tears to my eyes. It definitely resembles an alcohol flush reaction in appearance (I've never experienced this but have looked at photos and think this is important), but occurs 4-8 hours after I ingest kava. And I have tried every brand, grind, variety/extract/candy, as well as food, water, location combination possible. The only constant is the kava. Of course, now my husband really wants to try kava so at least my stash won't go to waste, but I want to be like, "Why now? I was drinking kava alone for years and as soon as I can't drink it, NOW you want to try??"
I'm hoping that NDG will chime in, since it was his idea to try taking the antihistamine before any kava: "Preventing, the dumping of histamine in the first place by antagonising the H1 receptor should have a much stronger effect."
NDG: Does the lessening of my symptoms (although definitely still present) when pre-loading with diphenhydramine support my previous conclusion of a developed allergy or does this seem to point to an enzyme issue, like in alcohol flushing? It is worth noting that in addition to taking the Benadryl before the kava, I only had a minuscule amount, probably less than one typical serving. Could the lessening of symptoms simply be dose dependent and not affected by the antihistamine at all, in actuality?
This truly is a mystery and, despite the fact that I still can't enjoy kava currently, I do like a good mystery.