Does anyone have experience with Urticaria in their dog?

My dog gets this quite regularly. Well, when I say regularly I mean about once or twice a year. I am almost sure it's not his food as it seems to be seasonal but neither I nor my vet can definitively say what causes it.Anyone else had/have a dog with this problem, and if so did you ever get to the root of the cause?

urticaria is basically hives which is basically allergies ... twice a year, if you live where there are definite separate seasons, the problem is pollen ... there is no treatment other than antihistamines for the symptoms ... i have worked out over the years my dog is allergic to tree pollens because as soon as they are out she is reactive ... wiping the dogs coat and feet when he comes indoors will stop him from ingesting the pollen and thereby making the allergic symptoms worse ... it is not surprising your vet can not diagnose, even doggie allergists (waste of money) can sometimes not be able to diagnose ...

I have a short hair yellow lab, he breaks out in wheals(urticaria) whenever he goes on grass. it's particulary worse in the late spring/summer season&autumn. it started off with his ears getting inflamed&they would end up infected repeatedly. his paws would then swell up&break out with nasty dermatitis after he'd been out on or near grass(this was before we knew about allergy), he then started getting really angry looking wheals on his body & his paws were in a bad way. we were constantly taking him back and forth to the vets who were puzzled by his condition, they even suggested getting him put to sleep!!! we then changed vets&we had a diagnosis within a wk! he's very allergic to grass, oak trees, wheat and chicken!!! the poor thing is now on steroids&antihistamines which are increased during summer mths, for the rest of his life, we have to avoid all the things he's allergic to(kinda hard when you take him for walks!). in the winter he doesnt suffer as much as the summers etc as long as we avoid the allergens etc.