Last October my mare was covered in hives. Two rounds of Dex worked until she came off the Dex and then her hind legs swelled up alarmingly enough for serum to be dripping down her legs. Antibiotics administered and she was ok thereafter. I took her down to my vet's to get her off this property and - of course, wouldn't you know it - the hives majically went away.
Now, six months later, she's come up with hives again --- any suggestions why?
She's not had any changes in feed, hay, supplements, not been wormed or given any thing else - I keep it all very simple. Now she's on plain hay that has been in my barn for several weeks. Nothing nchanged at all, not the bedding, footing, nothing...
Proud member of People Who Hate to Kill Wildlife clique
Hey, don't they sell the NAF D-Itch in Canada? If not, order some from www.corkfarmequestrian.co.uk and try it. I used it for a dog when it was sold stateside years ago, and it worked right away to cure his allergies whine pred did not.
I just ordered some for another Cother whose horses have allergies. Ask for Aimee or Claire at cork farm when you email them. I just bought some rain liners from them for Cloudy and Hattie's sweet itch hoodies. Nice people.
I had a horse that had the same thing happen as OP. hives then dex then swollen legs oozing serum. At the time, I was convinced that the dex suppressed his immune system and he got some kind of virus. I put him on omegahorseshine and probably coincidentally never had the hives again. I know that I'd ask more questions before using dex again.
Did she get rained on by any chance? This is a huge trigger for my horse. I'm dealing with rain induced hive aftermath now because I got caught off guard by the weather a few weeks ago and he was out, naked in the rain.