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“My pet smells like yeast!” Many diseases can cause an animal to “smell like yeast.” In this episode, Dr. Ashley Bourgeois, veterinary dermatologist and host of The Derm Vet podcast, joins Dr. Brittany Lancellotti to explain how cytology can help us figure out if the stink is really from yeast, or if there are other infections or diseases causing skin problems in your dog or cat. If your pet has ever had a skin or ear problem, allergies, or itching, this episode will help you understand why cytology is so helpful to your veterinarian.

This allergic Great Dane gets dog treats for letting the veterinarian take samples from his paw for cytology to look for skin infection. 

Welcome, Dr. Ashley Bourgeois

[00:01:04] Dr. Lancellotti: Welcome, everyone, to today’s episode of Your Vet Wants You To Know. I am very excited about today’s episode. We are going to be talking about something that is a little bit of a mystery to most pet owners. But I have someone who is here to help us break down that mystery. I would like to give a very warm welcome to Dr. Ashley Bourgeois. Welcome! 

[00:01:23] Dr. Bourgeois: Thank you so much for having me. I am so excited. This is definitely one of my favorite topics. 

[00:01:29] Dr. Lancellotti: Great. So before we dive into cytology, can you talk a little bit about your background and give our listeners an idea of where your experience lies. 

[00:01:41] Dr. Bourgeois: Absolutely. I went to vet school at the University of Missouri and graduated from there in 2010. I guess I should also give some recognition to my undergrad being at Iowa State University, which led me into the ability to go to vet school. I did a small animal rotating internship at Purdue University and then my dermatology residency at a private practice animal dermatology clinic in the Orange County area of Southern California. So the pro is we know our skin and ears very well, but I like to tell my clients that this is where my knowledge kind of stops. It’s just nice to really be specialized in something and feel really confident in that, but also recognize that general practitioners and other veterinarians have a vast knowledge of other things that we tend to forget.

[00:02:35] Dr. Lancellotti: Yeah, absolutely. I am not scared of telling my pet owners, “Hey, I’m not quite as familiar as your family veterinarian might be. I think this is a conversation that’s better had with them.” They are so knowledgeable on such a wide range of different things, while you and I are very highly focused on skin and ears, and I give them a lot of credit. 

Steeler and the Skin Infection

Dr. Lancellotti: So, in order to put this in perspective for some of the pet owners who may be wondering what cytology is, can you tell us about a pet that you may have treated, where a cytology was absolutely crucial in helping you figure out what was going on and how to treat that animal? 

[00:03:16] Dr. Bourgeois: Yeah. When I think about cytology, there’s actually a case that I saw years ago (when I was still practicing in California) named Steeler. The reason Steeler always sticks out in my mind is that it was really early in my dermatology career. He had been referred for a non-resolving bacterial infection which showed as crusting and some moist debris on his dorsal muzzle (top part before nostrils), and he had already been on several rounds of oral antibiotics. It would slightly improve, but it never fully improved. He was starting to get really uncomfortable and would rub and scratch his muzzle. But when I read his sample, what I noticed was that there really wasn’t any infection at all. There was no bacteria, nor yeast, and those are really common organisms for us to see under the microscope. He just had a ton of neutrophils, which is a type of white blood cell that can escape from the bloodstream and go to the skin if something inflammatory is going on. Then, I saw these really large skin cells that looked suspicious for something we call acantholytic keratinocytes. Essentially, that tells me that this is not a case of infection at all. In fact, it’s a case that we needed to biopsy, confirming that Steeler had an auto-immune disease called pemphigus foliaceus. And after a couple of months of treating him with various immunosuppressive medications, he was completely in remission. So it was just a case that really stuck out in my head because he was given antibiotics with really no cytology done. It absolutely could have been an infection based on the way it appeared, but it was an auto-immune disease, and that cytology allowed me to get on the right diagnostic path. 

[00:05:18] Dr. Lancellotti: That is a beautiful example of why cytology is such a powerful tool in helping us to guide our treatment plan to figure out how to get this animal comfortable again. How do we address what’s actually going on with them? Because you’re right- infection can create crusting and so can this particular autoimmune disease. By just looking at the animal, we can’t exactly tell what’s going on. Cytology is such a helpful tool. 

image of bacterial skin infection as seen under the microscope

How Does a Veterinarian Perform Cytology?

Dr. Lancellotti: You and I do cytology all day, every day, but most pet owners might not know exactly what it is that we’re talking about. Can you describe what cytology is for our listeners? 

[00:06:01] Dr. Bourgeois: I like to explain cytology as a snapshot of the surface of the skin, and what it is doing in that moment. There are various different ways that we would collect cytology, depending on preference of that doctor, the way that the lesion appears, or the area of the lesion on the body. We can either collect that through a direct impression smear (which is the most common way I collect it), by simply pressing the glass slide onto the skin or getting under the crust and sampling that. We can take a Q-tip and do a swab of a certain area. We can actually stick tape to the surface of the skin and then read that. No matter how we do it, the ultimate goal is to take a sample of the surface of the skin, stain it (with a diff quik, which highlights certain areas of infectious organisms or inflammatory cells), and then we evaluate that under the microscope. When we look under the microscope, we can look for various things: infection, bacteria and yeast, the type of inflammation that’s present, etc. Are there auto immune cells like we saw with Steeler? Are there cancerous cells that we didn’t expect? It’s just a way to see what the surface of the skin is doing. The nice thing is that when we get those results, most of us read them in-house. So within 10 minutes, we can really have a better idea of what’s going on with that skin. 

[00:07:40] Dr. Lancellotti: I think that’s a beautiful description of just how easy it is for us to collect these samples. This is a non-invasive procedure that we’re doing. Essentially, we’re really just touching the animal’s skin using different tools. Whether it’s a glass slide, a Q-tip, or a piece of tape, it’s not something that is going to cause any type of harm to the animal. It’s not something invasive that they need to be sedated for. And we have results immediately. As soon as we can look under the microscope, we can help to target what we want to do next with that pet.

Why does my dog smell like yeast?

Dr. Lancellotti: What are some of the other reasons why a veterinarian might recommend cytology to be performed on a pet with skin disease? 

[00:08:24] Dr. Bourgeois: Besides identifying those things like infection or autoimmune cells, we just know the skin changes all the time. The skin is ever-changing, so we need to assure things like infection that we identified a few weeks ago is actually responding to the therapy that we’re using. Sometimes, clinically, the pet can look a lot better, but then we’ll look under the microscope and actually find out that the organisms have changed. Or they’re microscopically not better, and if we stop that therapy too early, that pet could regress and do poorly. Seeing if our infections actually responded can be really important. Just knowing that we’re practicing the best medicine, we do not want to be stopping things like antibiotics too early. Resistant infections are something that we are already dealing with in today’s day and age, and it’s just getting worse if we don’t use things like antibiotics more appropriately. 

[00:09:29] Dr. Lancellotti: Yeah, cytology definitely allows us to provide much more targeted treatment when we know what it is that we’re actually treating. And I’m sure you’ve heard people say, “Oh, it smells really yeasty.” Well, those bacterial infections (and even some of the auto-immune skin diseases) that we see can have that same “yeasty” smell that actual yeast infections have. So if we only use our noses and we don’t look under the microscope to investigate what’s happening, we may wind up treating for something like yeast when there’s actually bacteria, or vice versa. The pet is going to start to feel so much better, much faster, when we know exactly what it is that’s going on. 

microscopic view of autoimmune skin disease in a dog

Why is Repeating Cytology Important?

Dr. Lancellotti: You talked about it being a snapshot- a moment in time of what’s happening in the skin. What do you think pet owners should know about the need for repeating the cytology? If their veterinarian just did it at the last visit two to four weeks ago, why do they need to do cytology again? 

[00:10:30] Dr. Bourgeois: It’s a great question, and I completely understand where they would be concerned, “Why do we need to keep repeating a test? Why do I have to keep paying for a test to be repeated?” But again, the skin changes very quickly. And when we sample the skin, especially if a pet is diffusely affected with lesions, we’re only really sampling a small portion of the skin. So if we have treated an infection, we want to know that it is completely resolved (including underneath the microscope), in that we do not need to expand our antimicrobial therapy any further, and that the pet’s totally in remission. Sometimes, we have pets who initially come in and there is a lot of secondary infection. When we see them back for their recheck and we check the cytology again, maybe that infection is much better, but now other things are more obvious. An example of this would be a ringworm case. Sometimes, if there’s a ton of bacteria on the initial exam, that can really mask what we see on the rest of the slide. So if we treat that and then reevaluate (if there’s still lesions or we’re just rechecking that infection), and we found that primary cause like a ringworm infection. Or like with Steeler- that case I talked about before- sometimes, those pemphigus cases are very infected when we first see them and we really do need to treat them with antibiotics at first. But then, we follow up, so we can figure out that primary problem that is causing issues for that pet. That’s why you’ll usually see dermatologists being very diligent if anything on the skin is abnormal or we’re rechecking an infection. We want to do a cytology again, because it’s truly the way that guides us through our diagnostic and treatment for that pet. 

[00:12:28] Dr. Lancellotti: Absolutely. With these pets that have skin conditions and ear infections, they do require a lot of long-term care. I tell owners, “It’s important to come back for a recheck exam, so that I can make sure that the infection is clearing.” Then, once the infection is cleared, and I’ve been able to confirm that using my cytology, we’ll talk about how to set up a maintenance plan to make sure that the infection doesn’t come back. So it’s important to do the repeat cytology so that you don’t have the infections relapsing. 

Does Your Dog Have an Infection?

Dr. Lancellotti: There are so many different benefits to using cytology. It’s a really crucial tool. What are the big takeaway points that you’d like pet owners to remember about cytology?

[00:13:11] Dr. Bourgeois: I really view cytology as the foundation of dermatology. It tells us so much, whether it truly is an allergic pet who’s struggling with infection. Let’s say it’s summer, and an ear infection’s caught up to us. I’ve had pets, in the past, that have always had bacterial ear infections. Then all of a sudden, they’ll just have a yeast infection and we don’t know why it changed. So it’s always important for us to identify what type of infection is there and how much infection is there, because that can really tell us what we need to do with our treatment, as well. But just like Steeler, it can also completely change what diagnosis we’re making. So that’s why it’s important to follow up. 

[00:13:56] Dr. Lancellotti: Yeah, it’s just like Sherlock Holmes always needs his magnifying glass in order to be able to do his job. We dermatologists need our cytology in order to be able to do our jobs, as well. I’m very thankful for you coming on the episode, today, to talk to our pet owners about cytology. A lot of family veterinarians are comfortable performing cytology and managing pets with skin and ear disease, but there’s also a link to find a veterinary dermatologist near you if you would like to consult with a specialist. If you have pets that have allergies or skin or ear conditions, I highly recommend joining the Facebook group, Your Vet Wants You To Know, to tell us about your experience with your pet. And if you have suggestions for upcoming episodes, you can comment in the group or contact me through the website. I encourage you to leave a review for the podcast if you found value from today’s episode and subscribe to stay up-to-date with future episodes of Your Vet Wants You To Know. 

Scratching the Itch

Russell Sprout gets his medicated bath with the help of the Aquapaw Slow Treater

[00:15:25] Dr. Lancellotti: I like to end each episode with a segment that I call Scratching The Itch. It’s a short segment that will highlight something- either a human interest story, a product, or a website that either provides relief or just makes you feel good. Hence, scratching the itch. Dr. Bourgeois, do you have something that ‘scratches the itch’ for you, today? 

[00:15:45] Dr. Bourgeois: Yeah. When I was thinking about what I could follow up with, as far as the importance of cytology and treating infection, I thought about how we often ask our clients with allergic patients to bathe and to do a lot of topical therapy. I have my own allergic puppy that I’m dealing with- and having to bathe and train her to enjoy bathing. Something that I have found helpful (you can find it pretty readily, and there are other companies that also produce a similar product) is called the Lick Lick Pad. You can find it online. Essentially, it’s very simple. It is just a product where you can stick something like peanut butter or canned food on it, which has little ridges in it that really catch that food, and then you can stick the other side to the wall of a bathtub. We know some dogs (and occasionally cats, if you have a cat that will allow bathing) do not really appreciate being in there, but we know how important it is to find a way to make it fun. To make it enjoyable can be really helpful. I’ve had a lot of clients who have found the Lick Lick Pad to be something that makes that request of bathing not so daunting. So that’s my little tidbit of a product which I find helpful in these allergic cases. 

dog licking peanut butter from a silicone suction cup mat stuck to a wall
Lick Lick Pad. Image from Amazon.

[00:17:06] Dr. Lancellotti: That’s excellent. I’m sure that will provide relief for many owners who have a hard time with bathing. I think that’s a great tool that you can use. We actually use that and the Aqua Paws Slow Treater in our clinic, as well, to help keep pets focused on one thing while we’re doing a physical exam with them. So it’s just something to make things more enjoyable for the pet and less stressful for the pet owner, as well. Thank you very much. That’s a very helpful ‘Scratching The Itch.’

[00:17:34] Dr. Bourgeois: Yeah, no problem. I live and breathe it with my own allergic dogs, so I thought it might be helpful.

[00:17:39] Dr. Lancellotti: Perfect. Thank you very much for joining us, today. I am very happy to have you provide your expertise for our pet owners.

[00:17:46] Dr. Bourgeois: Thank you so much for having me! It’s such an important topic, and I understand how frustrating it can be for pet owners. But we promise- cytology is definitely the best thing that we can do for these cases.

[00:17:58] Dr. Lancellotti: Excellent. Thank you all for listening, and I look forward to your next visit with Your Vet Wants You To Know.


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