@Kertong Ouch, that's one lousy allergy to have.
I'm guessing, though, that what's causing this might not be the actual cannabinoids (ie THC and the other related oils which get you high). So I suggest you try
water curing some of your bud.
The weed won't be as tasty afterwards, but then it could be the flavoursome terpenes that you're allergic to. Or it might be something else which gets washed out in a water cure. Anyway I think it's worth a shot, as taking antihistamines every time you want to vape surely can't be healthy in the long run.