Episode 108: Itchy Dogs (Part 1)

This week, we're joined by Dr. Tyler Jordan, Board-Certified Veterinary Dermatologist & Ph.D. Candidate in Comparative Biomedical Sciences, in support of Itchy Pet Awareness Month! Join us as we discuss canine atopic dermatitis, itchy dogs, food allergies and more!

Good Dog provides breeders in our community with free and exclusive access to puppy contract templates and legal resources created by our team of lawyers, specifically for dog breeders. If you're already a member of Good Dog, you can access these resources here. And if you're not a member, but would like to join, you can sign up here!

Transcript

Mikel Delgado [0:23] You are listening to the Good Dog Pod. I am Dr. Mikel Delgado, your host from Good Dog’s Health Standards and Research team. Today we are here with Dr. Tyler Jordan. He is a man of many degrees. He has a bachelors of science in marine biology from—I hope I say this correctly—Dalhousie University. Then he went on to earn his degree in veterinary medicine from the University of Guelph, Ontario Veterinary College. He completed a 3-year residency in veterinary dermatology at the UC–Davis School of Veterinary Medicine before heading to North Carolina State University to work on a PhD in the comparative biomedical sciences, of which he is still in progress! Dr. Jordan has written several articles about canine and feline dermatology, pathology, and on providing pro bono preventative veterinary care for animals owned by those who are homeless and marginally housed. We’ve been very eager to have a veterinary dermatologist on the podcast for some time now, so I invited Dr. Jordan to the Good Dog Pod because August is Itchy Dog Month at Good Dog. I think it’s Itchy Pet Awareness Month in the broad veterinary community. Dr. Jordan, thank you so much for joining us on the Good Dog Pod. 

Dr. Tyler Jordan [1:30] I’m so, so glad to be here. When you said it was Itchy Pet Awareness Month in August—what’s the color of the ribbon? What ribbons are we wearing during August? I don’t know! But thank you so much for the invitation. Really happy to be here.

MD [1:44] Whatever color the ribbon, I bet it’ll make my wrist itchy…

TJ [1:49] Maybe some sort of red.

MD [1:52] Perfect. So, I like to get to know my guests a little bit first. Maybe tell us why you ended up in veterinary medicine and why dermatology.

TJ [2:01] Sure. I’d be happy to. I’m originally from Ottawa, Ontario, Canada. I like to think my “out” and “abouts” have kind of blended into the background. They’re not as apparent. I’ve been in the States for 8 years, but I grew up in a family with a lot of health professionals. My father is an opthamologist. My uncle is a family physician. My grandfather is a dentist. My mother and two of my aunts are nurses. I grew up in various capacities within a medical family. I have memories growing up of sitting with my dad’s nurses while he gets called in to do emergency consults. I’ve worked at my dad’s office in various capacities. I always had an interest in what my dad was doing and the cases he was seeing. As many of us are exploring what direction our lives are going to take as we enter our undergraduate degree, our bachelor’s degree, I was always drawn to more courses that were oriented in animals. That interest is reflected in my day-to-day personal life; when you’re visiting the household of a relative or friends, I always gravitate towards the dog or the cat! Sometimes I’d spend more time with the pets than I do with the actual people.

MD [3:08] Been there!

TJ [3:08] Right, right. I feel like a lot of people can relate to that. So after my undergrad, I did two internships in wildlife rehabilitation. One in Ireland, one in British Columbia. It was then that I felt pretty solid in wanting to pursue veterinary medicine—marrying my interest in animals as well as medicine together. It seemed like a natural progression. Why veterinary dermatology? While I was completing my veterinary degree, I knew I wanted to pursue more advanced clinical training. I knew I wanted to gain in-depth expertise and knowledge in one particular field. Throughout that school, I was exploring a lot of different specialties. There was a time when I wanted to be a veterinary cardiologist. I wanted to become a veterinary ophthalmologist. Emergency and critical care specialist. It wasn’t until my clinical rotations in my last year, as well as when I was doing my rotating internship before my residency at Ohio State, that I was first exposed to veterinary dermatology. A few things I gravitate towards in that field: one is it’s a field that’s incredibly visual. All of the things that we’re worried about, we can readily see with the naked eye. We can touch. As many people listening to this podcast know, you can also smell all the skin lesions too. I’m a very visual learner. I liked how easy and how dramatic some of the diseases that we see routinely were. A lot of skin diseases—we can make dramatic improvements in an animal’s quality of life, and the owner’s quality of life, as well as the general appearance of that animal relatively quickly. I would say unfortunately the vast majority of skin diseases that we see in companion animals, at present, we don’t have the ability to cure. But we can manage them for the duration of an animal’s life. We can provide animals with skin disease a high quality of life, making them as comfortable as possible for as long as possible. But that usually has to take place over the duration of an animal’s life, and in doing so, we build strong relationships with not only the pets but their owners as well. I found developing those strong and lasting relationships with the animals I was seeing, as well as the owners, to also be rewarding. It wasn’t like I saw you one time and I never see you again. We get to follow that animal and sometimes see them grow up, which I really enjoy. That is why I pursued veterinary dermatology, per se. 

MD [5:28] Nice. Very nice. I had no idea. We’re going to have a guest in a few weeks who does research on the effects of having an itchy pet on the owner. Psychological difficulties. So I’m excited to learn more about that. I hadn’t really considered the impact on the owner seeing their pet itch all the time.

TJ [5:45] It’s a huge problem. It’s a multifactorial problem. It’s not only impacting the animal, but the owners who oftentimes feel helpless and hopeless while trying to provide relief. That’s interesting. 

MD [5:56] What is the life of a veterinary dermatologist like? What is your day-to-day when you’re working with itchy pets?

TJ [6:04] I would say when I first started talking to people about what I do, they’re like, “What are you?” I’m like, “I’m a veterinarian.” Then they’re like, “Small or large animals?” I’m like, “Anything with a skin problem.” I think a lot of people don’t realize that veterinarians can also specialize to the same extent as human physicians do. For an average veterinary dermatologist, the majority of the cases that we see are composed of dogs and cats, with dogs making up the lionshare of that. Depending on the type of clinic you’re working in, especially if you’re working in a vet school, you’re also sometimes asked to consult on any species with a skin problem. When I was doing my residency at UC–Davis, that included horses, cows, pigs, goats, sheep, hamsters. I saw a red-tailed hawk once. Anything with a skin problem that comes to us. The majority of cases are all referred in by family veterinarians. Generally speaking, if a dog owner notices a problem in their dog, either they’re limping or there’s diarrhea or a skin problem, they usually first go to their family vet, where they get vaccines, spays, and neuters. Generally speaking, for dogs with skin disease, the dogs that I see—family vets have tried a variety of different treatments. Either that animal’s skin disease is completely unresponsive or the disease gets better but comes back once the medications are stopped. For owners in those situations, when either we have a skin problem that doesn’t respond to treatment or keeps on coming back, that’s oftentimes when they refer to us. Part of our day-to-day, in between seeing appointments, is trying to get a handle on everything that has happened before that animal comes in. What has been tried? When did this start? Again, we see a lot of dogs. The majority have varying issues with itch. That is by far the predominating problem. But there is also a sprinkling of cats and other species. A lot of these cases are referred in because things haven’t been working with the family vet. That’s the population of dogs that we see as veterinary dermatologists. 

MD [8:14] Let’s talk about canine atopic dermatitis. What does that mean? 

TJ [8:19] As I’ve kind of alluded to, this is the most common skin disease that we see in dogs. Depending on the time of year and where you practice, it can take up to 75% of your caseload. Canine atopic dermatitis is also commonly referred to as “environmental skin allergies.” The podcast listeners may have heard it described in that way. It’s a disease that bears a lot of resemblance to eczema in humans. Canine atopic dermatitis/environmental skin allergies (whatever you want to call it) is a chronic skin disease that waxes and wanes, that’s associated with moderate to severe itch, as well as skin inflammation. What this usually looks like: generally speaking, dogs with this disease first show signs between the age of 1-3. They either have varying degrees of licking, scratching, chewing, biting, rolling, rubbing, or scooting that involves (generally) the ears, around the eyes, the mouth, in between the toes of all four feet (tops and bottoms). They can chew their inner wrists. They can nibble the inside of their front legs like they’re corncobs. Scratching and rash. Armpits and groin. That’s the textbook picture of what canine atopic dermatitis looks like. As an animal, it’s self-traumatizing, the scratching—they’re breaking down their skin’s normal defense mechanisms. Then we run into secondary bacterial and yeast infections in all of those sites. Classically, dogs are usually prescribed various treatments and, usually, the signs will resolve with antibiotics or anti-itch medications. Classically, they always come back once those medications are stopped. These signs can first start very early in life. Sometimes they’re seasonal. There are certain times in the year when they’re worse than others. In other dogs, it’s a year-round problem. In some dogs what was once a seasonal problem becomes a year-round problem with age. We know that as an animal gets older, the symptoms become more and more severe with time. What was once a dog that only maybe got a mild ear infection here and there as a puppy is now licking, scratching, chewing, biting year-round, their whole life, years down the road. The problem that we have is we can recognize this disease. Well, veterinary dermatologists that are trained to recognize it can. It’s not a challenging diagnosis to make. But the how and why this disease occurs is less clear. It’s believed that dogs with atopic dermatitis, their skin doesn’t do a good enough job at preventing things in the environment from penetrating into the body. Normal skin should be a pretty solid barrier that nothing can penetrate through, whereas a dog with atopic dermatitis—there’s some dysfunction. It’s not as rigid of a barrier. Things that are normally within the environment, like pollens in the grasses, trees, weeds, house dust mites—they not only land on the skin but then penetrate deep down and trigger an allergic reaction, which can get worse with time. Another key feature of atopic dermatitis is there’s very well-defined breed predispositions. There are several breeds that we see very regularly with the problems I just listed. We see a lot of Golden Retrievers, Labrador Retrievers, German Shepherd dogs, French Bulldogs, West Highland White Terriers, and Pitbull or bully breeds. Those are the ones I see most commonly. It’s not that we can’t see it in other breeds, but those are the most common dogs. For those that are unfamiliar with atopic dermatitis, that’s kind of my “quick Wikipedia.” That’s what we mean when we talk about that disease.

MD [12:12] Now that you’ve explained the skin barrier issue, it makes sense, but the fact is that the dogs can present similarly, right? They’re itchy. They’ve got redness. But there can be several different causes. How do you then determine: Is it pollen? Is it ear mites? Is it X, Y, or Z?

TJ [12:30] Perfect. Itch is the most common symptom that we are seeing in the clinic. There are a lot of different diseases in which itch can be a component. The skin has a relatively limited vocabulary. What I mean by that is it has only so many ways to respond that we can detect to a vast number of diseases. Part of putting on our Nancy Drew hat to figure out what the underlying problem is, there’s a few things we can start with. One of the first things we do when we have a dog that’s presenting with itch is getting a very thorough understanding of the history. When did the itch start? What parts of the body are affected? Distribution or what parts of the body are a really important aspect of us prioritizing what diseases we think are at play or are our top differentials. What has been done in the past? How has an animal responded to treatment? Are the problems seasonal or nonseasonal? One of the first things we do when we hear “itch” is try to get a sense of the history. We’re oftentimes relying on a dog owner’s ability to perceive these things. I can get info from a dermatological exam, but there’s so much in dermatology that’s based on getting an accurate representative history from the owner. Let’s say we have a dog that’s presenting with itch, rash, ears, eyes, mouth, paws, armpits. My Spidey Sense is tingling that we might have canine atopic dermatitis. I can’t look at a dog and diagnose that at the first visit. There are a few hoops that we need to jump through. Whenever I’m presented with an itchy dog, getting an idea of the history, yes, but one of the first things that I want to rule out or at least evaluate for are secondary bacterial and yeast infections. Those are common complications when an animal is chewing, licking, biting. They’re breaking down their skins’ defense mechanisms, and we oftentimes see bacterial yeast infections, which oftentimes makes the disease much, much worse.

MD [14:31] So that’s not the cause of the problem but it’s exacerbating it. 

TJ [14:35] Correct. That’s right. Although it’s kind of a bit of a Pandora’s Box. People are looking into the microbiome and how the normal populations of bacteria influence the development of atopic dermatitis. That’s a whole other can of worms that I won’t get into. But bacterial and yeast infections are a secondary problem. They do not cause atopic dermatitis. They are a result of it and make it much worse. We want to evaluate for those, as well as treat them appropriately. Two is I want to make sure that the dog as well as every animal in the house is on appropriate flea control. Fleas are known to be an allergic trigger and can dial up any kind of itch inflammation that’s present. A lot of the flea control products that we use treat a number of other parasites. Just making sure that we’re ruling out parasites more globally, different types of mange mites, lice, fleas—that’s another thing that I just want to take off the table. Lastly, once you evaluate for secondary infections, potential parasites, then: Is this a dog with atopic dermatitis? Is this a dog with food allergies? Or is it a combination of the two? Dogs with food allergies can look identical to dogs with atopic dermatitis. Another hoop that we jump through/the way that we figure out which disease is at play is oftentimes screening an animal for a food allergy with an elimination diet trial. I guess the short way of answering your question is how do we figure out what diseases are at play, getting an accurate history, giving a dermatological exam as well as seeing how animals respond to different therapeutic trials. If I get them on appropriate flea control, if I treat the infections, what do things look like afterwards? When I peel back this layer of the onion, what does it look like underneath? 

MD [16:57] That’s a perfect segue into my next question, which is can we talk about food allergies? I don’t know if it’s because food is something you can control. I can’t control what trees and pollen are outside my house or what allergens might be blown around. I think people say, “I can control food.” And they are blamed a lot for skin problems. Are they a likely cause? Should people be experimenting with diet before they see a veterinarian if their dog is itchy? What’s likely behind a food allergy leading to an itchy dog? How would people even approach that?

TJ [17:31] That’s a great question. Before I dive into my answer for that, whenever we’re approached with an itchy dog, dogs that develop allergies are predisposed to developing several allergies. When I talk about food allergies, flea allergies, atopic dermatitis, and environmental allergies, it’s not so much that a dog has only one or the other—but they can have a combination of all of the above, plus secondary infections. Whenever we’re approaching an itchy dog, it’s important that we address all the reasons as to why an animal may be itching. Let’s say, for sake of argument, we have a dog with food allergy, environmental allergy, as well as infections. If we only treat the infections, things might get better, but you won’t resolve the problem. If you only put an animal on an elimination diet trial but don’t control the atopic dermatitis and the infection, we’re not going to have a successful outcome. Oftentimes, there’s a lot of things that are contributing to an animal’s itch. It’s not so much just one. So part of the way that we’re figuring out what the issues are is by casting a broad net and eliminating one problem, one thing at a time. Oftentimes, it’s multifactorial, meaning I can’t just change the food and everything is going to go away if a dog has other problems that we’re not addressing and treating. With respect to food allergies, this is one of the most common things that people look into. When I see dogs on a referral basis, they tried out all these different diets. They’ve done blood testing for food allergies. They’ve removed the chicken and things are no better or no worse. Dogs with food allergies can develop an allergic reaction to things within their diet after eating the same diet for 5, 6, 7 years. It does not have to be a change in their food for them to develop an allergic reaction to something in the same diet they’ve eaten their whole life, down the road. It’s either the protein or carbohydrate source that an animal develops an allergic reaction to. In dogs, the most common food allergies are to beef, dairy products, chicken, wheat, and lamb. Those are the top things they can develop a food allergy to. What are symptoms that may suggest an animal has a food allergy? There’s a number. 1) Dogs with food allergies can look identical to dogs with atopic dermatitis. Ear infections, itch, paws, eyes, armpits, groin. Dogs with food allergies can also develop chronic GI signs. That makes more sense. Vomiting, diahrrea, gassiness, chronic recurring anal gland impactions/infections. Sometimes even just having more than 3 poops per day has been associated with a food allergy. If you’re hanging out at home with your dog and you can hear your dog’s stomach rumbling. In the biz that’s what we call borborygmi. That’s also been associated with food allergies. Dogs with food allergies can also develop hives, just like hives from top to bottom after eating something they’re allergic to. The reality is, for dogs that I see (dogs that have cutaneous manifestations of food allergies; I’m not talking about just GI signs but cutaneous manifestations), roughly 10-25% of dogs that have itch may have underlying food allergy. But that doesn’t mean that their itch is coming exclusively from a food allergy, right? It can also be fleas. It can also be infections. It can also be pollen and mold. The way that we approach this can be very confusing, especially because there’s a number of laboratories out there that offer blood testing or saliva testing to screen animals for food allergies. But with the tests that are currently available, these are completely unreliable. You can get the test result that says: Based off of a blood test, your dog is allergic to chicken. And you can feed that dog chicken, and there can be no flare. The blood test that we have for food allergies is completely unreliable. I guess when I start to think about screening an animal for a food allergy is when I have a dog that comes in that’s experiencing some degree of itch; they have concurrent GI signs; and it’s a year-round problem. People aren’t necessarily switching the diet depending on the season. That tells me that I probably want to screen an animal for a food allergy. We also think of food allergies as manifesting younger in life. So if I have a dog with all the listed skin problems beneath the age of 1 here, that would also be a reason as to why I might recommend screening an animal for a food allergy as one of many flare factors that may be contributing to their overall skin health. This also leads into another complication: what diet do you use to screen an animal for a food allergy? A lot of people are just choosing diets over the counter. We oftentimes have to use a prescription hypoallergenic diet because, despite what the labels will tell you on over-the-counter diets (“This is only salmon and sweet potato!” or “This is only goat and lentil!” or whatever), oftentimes over-the-counter diets are contaminated with other protein sources that are not on the label while they’re manufactured. This is not to say that they have salmonella or there’s some recall. But unless those manufacturers are disassembling the machines or steam-cleaning them down, there’s bound to be a little bit of something that they made before that ends up in the bag that you’re feeding your dog. Whenever we’re doing a diet trial to screen an animal for a food allergy, we usually do it with a prescription hypoallergenic diet that contains proteins and carbohydrates that that animal has never been fed before. We’re feeding that for at least 8 weeks before reintroducing the former diet. I think food allergies get more attention than they probably should because, relatively, it’s not the most common cause for itch. From my personal experience, dogs that have food allergies also have atopic dermatitis also have flea allergies. It’s just one piece of the puzzle that I think is important that people address, but I think it gets a lot more attention than it probably should. Not that it shouldn’t be addressed! But I think people focus on that disproportionately. 

MD [23:45] That’s what I suspected, which is why I wanted to ask you about it! Alright.