I agree that you should take your dog to your vet, and ask what might be done for the allergies.
My vet prescribed for Camellia, any of three different antihistamines:
1) Cetirizine hydrochloride (generic Reactine) - 10 mg. (a full human dose!) to be given once daily (it's apparently a time-release pill). She prescribed 7.5 mg, but said the 10 mg was okay.
2) Chlorpheniramine (generic Chlortripolon), 2 mg (half a 4 mg tablet) up to three times daily. Again, this resembles a human dose, though humans might take 4 mg three times daily.
3) Diphenhydramine hydrochloride (generic Benadryl); 20-40 mg up to three times daily. I got the 25 mg tablets, and rarely, give her 25 mg; more often, 37.5 mg (a caplet and a half).
Camellia weighs 8.7 Kg (about 19 pounds); she's a BIG Hav! Doses for smaller Havs might be somewhat less.
I tried the Reactine first. Kept at it for a few months, but it didn't seem to do that good a job. Next, I tried the Chlortripolon, and that didn't seem to work very well either. So then I tried the Benadryl - and THAT does help, quite a lot.
My vet was very enthusiastic about the Reactine, and maybe that would work for your dog.
If you can possibly avoid using steroids, please do, as there can be long-term consequences, including a tendency to develop diabetes - and - I had a diabetic dog; you don't want that! It's a lot of work, and fairly expensive to manage (though diabetes in dogs is a very manageable disease, and need not shorten the dog's life - but the scheduling is rough for the humans, because typically, you need to feed every 12 hours, no food between meals, and inject insulin every 12 hours, shortly after feeding.
My vet pointed out to me that Camellia's allergic dermatitis (atopy) results from her missing the natural skin barrier against allergies that dogs and humans normally have. So I use a special shampoo and spray, bathing once a week (religiously!) and spraying after the bath, and then once mid-week, between baths. The shampoo and spray replace the missing skin barrier!
Anyway, I'm suggesting you might talk this over with your vet.
MUMMY! It's past bedtime! (00)
So it is, Camellia; I'm coming! ;-^
Mon, 19 Mar 2012 22:12:54 (PDT)
Maybe your dog has something like that - a missing skin barrier! It's explained here (my vet gave me this link):
The shampoo and spray I use are by DOUXO, and my vet-insurance company, Trupanion, is covering 90% of the cost for me. It's expensive here in Canada, where I think you can only get it from vets. I've put in three claims so far, and they encourage me to keep submitting claims, and will pay forever! (for the rest of Camellia's life). It's the calming shampoo and spray.
If you click on the Product Datasheet, it tells you how to use the stuff.
If you're in the U.S., though, you might be able to get it fairly cheaply, at amazon.com.
You might want to check out the possibility, with your vet, that your Hav is missing that skin barrier! The shampoo, spray, and antihistamines combined are working well for Camellia; keeping her quite comfortable most of the time.