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When Spring’s again you’ll bring again …..

August 7th, 2013

No,not tulips from Amsterdam but itching, scratching dogs and cats to Millpoint Vet Centre. So for my first blog after such a long break we just have to have a chat about allergies.

Perth is the allergy capital of the WORLD. Think how many kids and adults you know with asthma. Cats and dogs can get asthma but  far more common reactions to the allergies they suffer are skin and ear problems. I reckon every second dog in Perth has some degree of allergy and only the severity is in doubt. Lots of cats have allergies too.

Most of the allergy cases I see have allergies to grasses and pollens. That’s just the way it is when you have the amazing variety of plants and trees  we do in WA. Most of these allergies are, at least to start with, seasonal and the peak time for them is Spring (with a second and lower spike in Autumn). Dogs and cats can, of course, be allergic to house dust mites, moulds,insects and food too. These allergies tend not to be seasonal.

Dogs and cats can present a little differently so I’ll deal with my doggy patients first and add a few extra notes for the pussycats.

Typically itchy red skin is the first sign of allergy.It’s not unusual for dogs to scratch occasionally but any persistent itching (the technical term is pruritus) is suspicious. Classically the face,feet and underneath of the dog (belly,armpits,groin) are affected. If the allergy is left untreated severe self trauma may result and secondary infection occur. I read somewhere that around 30% of allergy cases present ONLY with ear problems. From my own experience I would agree and almost all ear infections I see are secondary to a primary allergy.

So how do I treat these dogs? For skin allergy cases in practice there are three treatment options. If the degree of itching is mild and especially if the dog is young  I prefer to trial anti-histamines with fish oil and shampoos as my first line of therapy. My reasoning here is that, if they are effective, you can give your dog anti-histamines every day for the rest of their life without any significant side-effects. Unfortunately there are many cases where this approach doesn’t work or where the dogs are chewing themselves raw and more urgent relief is needed.

My second option is to trial these dogs on cyclosporin. This is an immune-suppressive drug with a powerful anti-allergy action. Side-effects are limited usually to vomiting after dosing (and there are ways round this for most patients). It would be my favoured next step for all patients with atopy (allergy to grasses/pollens or other allergens in their environment) but cost prevents its use in dogs over 20kg for most owners. Treatment failures may occur if a/ the dog does not have atopy or b/there is an untreated secondary skin infection but otherwise it is VERY effective.

And thirdly, if the budget is limited or the dog is large there is prednisolone, a powerful anti-inflammatory corticosteroid. Now oral prednisolone at the lowest effective dose every second or third day can be a reasonable treatment protocol for an older dog but there are side-effects with long term use and we need to discuss these in a consultation so you, the owner,can make an informed decision on treatment. If possible, corticosteroids administered as creams or sprays are preferred as the side-effects associated with topical use are far less marked.

You will see that as I started to outline the therapeutic options above I included the words “in practice”. There are excellent veterinary dermatologists in Perth who can test your dog or cat for allergies and prepare a specific cocktail to desensitise your pet to their allergens but that falls outside the scope of this post.

Now for the pussycats. They can present a little differently with patchy hair loss and no apparent itching because they are very good at doing their scratching when you’re asleep or out. When I graduated nearly 30 years ago there was a whole category of feline alopecia (hair loss) and overgrooming  associated with presumed neurosis. As allergy testing became available more widely these cats have been recognised and reclassified as allergy patients.

Cats can respond very well to certain anti-histamines. There is no formulation of cyclosporin licensed for use in cats so if anti-histamines are not effective or not appropriate then I use oral prednisolone,often at higher dose than in dogs because if you can’t stop the itching quickly those cat claws can do an awful lot of damage to their own body.

I hope this brief run-through of allergy treatments will prove helpful if you need to bring your pet to see me. You won’t be alone!

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