"Super-hive" mystery solved

FINALLY! I know what's causing Dozer's insane hive outbreaks.

Two weeks ago, I took Dozer to the regular vet to treat staph lesions that were popping up here and there. The weekly baths and occasional Zyrtec just weren't cutting it. The vet prescribed a standard round of prednisone (to stop the itch) and cephalexin (to stop the staph).

Today, as soon as I saw the telltale pinpricks of oncoming urticarial vasculitis, ("super hives") I called the dermatology/allergy vet. (Well, first I screamed "NOOOOOOOOOOOOoooooooooooo!!!" and then I called the vet.)

What urticarial vasculitis looks like in the first few hours.

After looking back through his files, the derm vet confirmed what we'd already suspected but now seemed pretty conclusive: cephalexin allergy.

Ironically, today, after I reviewed some historical blog posts about Dozer's hives (like this one in 2009, this one in 2010 and this one earlier this year), I saw that he'd been taking cephalexin, an antibiotic, in every case.

Why wasn't the allergy deduced years ago? Because the hives never happened at the beginning of a cephalexin course—only at or near the end. Dozer could go two weeks on cephalexin and completely finish the course without a reaction, only to break out in hives a few days later, while taking no medications at all.

This mystery was also solved today, because the derm vet noted that Dozer usually gets prednisone or a cortisone shot at the same time that he's given the cephalexin. Although the point of the steroid is to cut down the itching from the staph, these steroids stop all allergic reactions. Period. Including the reaction to the cephalexin. After the short steroid course tapers down, there's nothing stopping the hives anymore. Thus the delayed reaction.

Six hours later--not looking too bad this time!

Prednisone and a much larger dose of Zyrtec were the order of the day. I'm loving the Zyrtec (over the Benadryl we used to give) because it knocks Dozer right out. I know the D is loving it, too, because he goes right to sleep. No itching, whining, panting, tummy upset, or any discomfort.

Sleeping soundly... with his face inches from the space heater.

Well, as they say, hindsight is 20/20.

First thing tomorrow morning, I'm calling the regular vet to ask them to flag this allergy in his file. No more cephalexin!!

Urticarial Vasculitis

Thank you very much for your well wishes sent to Dozer!

He is doing much better today, and today we have a fancy name for his crazy allergic reaction: urticarial vasculitis.

"Rhymes with treat!"

We went in today and the dermatology vet got her first look at Dozer after his hive attack.

The hives themselves are pretty much gone. Dozer looks totally normal when he's standing around.

Clearly feeling fine today.

The derm vet glanced him over and noticed the smaller bumps on his rear leg and said "Okay, so these are the hives?" Translation: "I don't get it. Why are you here?"

I said, "Those are some leftover hives, but you really should look at his stomach." We got Big D to lie down and stretch out, and I spread his rear legs for the full effect.

Day 3. Now looking rather like poison ivy or ringworm.

The redness is not quite as purple today, but it has spread so that you can see it all the way down his legs, even through his fur.

For the first time ever, I heard a vet say "Jesus Christ!" Followed by a lot of "Oh wow... Wow... Wow... This is so red... wow...."

I said, "This is day three. It looks different every day. I have photos of the last two days on my flash drive."

"I... wow... Oh my gosh..." It went on like this for a while as she and her assistant stared at the train wreck that was my dog.

After she had gotten past the shock and awe, the vet asked if she could take Dozer in the back and show him to the interns. She also took my flash drive and copied the photos, evidently wanting to use them in her lectures.

Which was all fine and good, but I really wanted to know what the heck my dog was suffering from.

Other than goofy-adorable syndrome, of course.

Anyway, after she brought Dozer and my flash drive back, and after consulting with interns and a few other vets, the derm vet said that Dozer had an episode of urticarial vasculitis.

Basically, urticaria is a serious case of hives, and vasculitis is when the blood vessels get inflamed and leak blood and fluid into the skin. In other words: Dozer's hives were so massive that they caused extensive bruising. Vasculitis also explains why the redness expands and turns interesting shades of purple, green, and brown over a period of days--the same way a bruise does.

Why and what to do about it are the harder questions to answer. The derm vet said that it could have been caused by a bug bite, a drug (like the cephalexin), or food allergy. Since D is on the rabbit-based food only, we don't think it's food. It could be a reaction to cephalexin, so we've decided to stop giving that.

But the most likely culprit is a bug sting, of any kind, from tiny fire ant to big red wasp. A bug sting would explain all of the previous hive outbreaks that Dozer has had, because he has always developed the hives after going outside for a potty break.

No matter what caused it, the vet has recommended that we try giving Dozer a daily antihistamine. That should put a damper on his daily allergies, and also stop these hives before they have the chance to go nuclear.

Most dogs would get Benadryl, but we are going to try hydroxyzine. You would not like Dozer on Benadryl. Nobody likes Dozer on Benadryl.