My Dog Has Food and Skin Allergies...I NEED HELP ( or how to treat an itchy dog)!

If you think that your dog is itchy because they are suffering from a food allergy or environmental allergy like pollen then this is what you need to know!


Question number four is all about food or environmental allergies.

So we've got a dog who the owner says he either has food or environmental allergies (that's also known as atopy), and they've been giving him a specific diet to try and find out what foods he's allergic to. But it's been really tough trying to pinpoint and find out exactly what that is. And he's just flaring up constantly, he's really uncomfortable and now he's got a lot of little bumps in between his paws and on top of his body that are causing him to be constantly itchy. They're also using a shampoo, but the results have yet to be seen.

He's still really uncomfortable and the owners aren't enjoying seeing him in pain. They want to get to the bottom of his problem and find something that works.

So to start with, there's no mention of what's been done to diagnose the problem as allergies in the first place. So it's really important when we've got an itchy dog for any apparent reason and with any particular lesions to rule out an underlying parasitic infection. So mites or fleas and fleas are incredibly common. We also need to rule out drug reactions and organ disease, which will often be done on history. We also need to rule out secondary bacterial or yeast infections.

It really depends on the presentation and there are a number of things that we'll do when we're presented with these patients. We’ll use a flea comb to brush their hair. It's surprising how common evidence of fleas being present is when they're not immediately visible with just a quick cursory look. So hair brushing is important. We take plucks of hairs as well and we can do skin scrapes and tape preps to look under the microscope for evidence of mites or bacterial or fungal disease. We can also take biopsies, we can run blood tests and we can also do treatment trials, for example, with parasitic anti-mite treatments.

There’s a number of different things we can do and we should be doing to rule out some other things before we're jumping into the diagnosis of allergic skin disease because ultimately not all itchy dogs are allergic and that's really important to consider. It might look like an allergy, but it's important that we rule out some of the other more common problems first as well.

So once we are happy with that diagnosis of allergic skin disease, there are a number of things we can be allergic to.

The three ones that I really think of, we've got flea allergic dermatitis, we've then got atopic dermatitis (so that's an allergy to environmental factors - things like pollens and dust), and then we've got food allergies.

Now probably flea allergic dermatitis and atopic dermatitis are the most common, but food allergy is definitely something to think about and it is very often the case that a dog who is allergic to one thing is also allergic to other things.

When it comes to atopic dermatitis and also flea allergic dermatitis, there is blood testing that we can do and that we can run to look at that or we can do something called intradermal skin testing. This is where we inject little bits of potentially allergic compounds under the skin and see what their reaction is. So that's something that's often done by a dermatologist, but it may be that your local vet will offer that as well. So we can do those things to try and find out what it is that an allergic dog is actually allergic to.

This doesn't actually work very well for dietary allergies though. Now there are some blood tests that are offered, but I don't consider them to be super reliable. So it's not really something that I consider as an option in the majority of patients. To find out if a dog has a food allergy, we need to do something called a diet trial.

So food allergies, they're most commonly due to the protein or the meat portion of the diet. So that's generally your chicken, your beef or pork or such like. And that's really despite what people may say because really allergic skin disease resulting from grains is actually pretty uncommon. It is a thing, but it's pretty uncommon.

What a diet trial then involves, is feeding a novel or a new single source of protein or a hydrolyzed diet and what a hydrolyzed diet is, is where they've taken a chicken molecule for example, and then broken it down into really small bits that the body doesn't recognize as chicken. So that's effectively a novel protein that the body won’t recognize and then won’t react to. The diet that actually the owner mentioned in the original question that they'd been feeding fits into neither of these categories. It's actually got lots of different proteins in it, which is one of the selling points, and it is grain free. So great if you know a dog is allergic to grains, but like I say, they're very much the minority.

Now the difficult thing about diet trials is that you must feed this single food for up to 12 weeks before responses are seen. Now typically it's seen a little bit sooner than that, maybe six to eight weeks but really we need to feed it for 12 weeks before we can rule out a food allergy. Sometimes too, you'll need to feed two different diets before you can rule it out completely, but they must eat nothing else. So if they get any other treats, if they get anything else then that can ruin all of the good work.

So you can see that can be really challenging. That's three months worth of feeding one diet with no other treats, no other snacks, not picking anything up off the street and so it's really tough to do that well.

Now there are also frequently also elements of atopic dermatitis in dogs that have a food allergy and there are a number of different treatments that we can do that are really varied. It can involve medications like steroids or Apoquel or Cytopoint. It can involve shampooing, it can involve skin diets. They are slightly different to our hypoallergenic diets or a food trial diets, although these can be used as a skin diet as well because that's ultimately what they're designed for (but they are often a bit more expensive).

We can feed diets, we can add fish oils or essential fatty acids to the diet as well. These have an anti-inflammatory effect and improves the skin barrier. We can give antihistamines as some dogs will respond well to antihistamines. Others though it makes no difference and others it causes sedation but that's certainly something to consider.

We definitely want to be giving parasite preventative products.

We can try and avoid the allergies if at all possible. So if you've had a blood test or if you've had the intradermal skin testing, then we can try and avoid that problem item. That’s generally pretty difficult, but it may be if your dog’s only allergic to one thing that's possible and then it's also possible that we can give a desensitization program. So this is effectively a vaccination for what a dog is allergic to. A dermatologist might give us a course of injections and that effectively is a vaccination against whatever it is we're allergic to.

And then one other big treatment of atopy or atopic dermatitis or flea allergic dermatitis and dietary allergies is to control flare ups and secondary infection. Whenever we've got a flare up and a dog is becoming itchy and the skin is becoming inflamed, then very often we get an overgrowth of the normal bacteria or yeast that are present on the dog's skin. It's very important that we treat that because that will continue to cause itching even if we get the underlying allergy under control. That infection will continue to cause itching, so we need to treat that as well.

At this point it's also worth saying that skin conditions, and especially allergic skin disease, it can be incredibly frustrating. There's no one size fits all approach. It can involve a lot of playing around with a management plan to find out what works for that individual patient. We could give everything that I've discussed and that would probably work, but it would also cost a fortune, it would be time consuming and difficult to give all those medications in one go.

So we need to play around to find out what's the most effective way to manage this disease for each individual. And so for that you're going to need to work closely with your vet.

And then finally, if your vet is really struggling, if you're not getting anywhere, then that's where referral to a specialist dermatologist is a really important step. One that's incredibly useful for those really itchy, really allergic dogs that don't seem to respond to anything.

The above is a transcript taken from “The Dr Alex Answers Show”.

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