I had an outbreak of idiopathic hives that went on for over a year. I tried various things and eventually found cetirizine, which was the only thing that provided any relief at all. I read a lot online about suggested treatment for hives and found that doctors sometimes recommend taking up to 40mg a day. I slowly upped my intake to 40mg at one point, but felt a bit weird when I did so I cut back. I'm still alive, so the increased dosage wasn't that dangerous! I wouldn't hesitate to take 20mg a day. Of course, YMMV.

I've also read that you want to be careful about taking them long term since you could end up with hives like I had! I think that's true of other antihistamines, so I'd be careful about going on a long-term daily regimen.

Excellent, practical Ticker! Love it! Thanks so much!