The rare skin disease, pemphigus foliaceous (PF), is an autoimmune condition in animals and humans. Veterinary Dermatology Specialists Dr. Alicia Webb and Dr. Brittany Lancellotti delve into the signs, diagnosis, and treatment options for PF, which can cause severe itch, crusts, pain, fever, inappetence, and weight loss in dogs and cats. Dr. Webb shares a case about a dog named Piper and highlights the importance of tailored treatment plans to get the disease in remission and adjust medication for a safe solution. The episode also includes information about the disease’s prognosis and the need for long-term management.
Table of Contents
Welcome, Dr. Alicia Webb Milum
Dr. Lancellotti: Welcome, everyone, to today’s episode of Your Vet Wants You to Know. Today, we’re going to be talking about a rare skin disease that most family veterinarians may not see throughout their careers, but as a veterinary dermatologist, this is something that I treat on a fairly regular basis. I’ve brought on the show today, one of my very dear friends, Dr. Alicia Webb. She is a veterinary dermatologist out in Oklahoma city, and she is going to be helping me talk with you about a disease called pemphigus foliaceous. Welcome, Dr. Webb.
[00:01:35] Dr. Webb: Thank you so much for having me. I’m pleased to be back, Dr. Lancellotti.
[00:01:39] Dr. Lancellotti: Your episodes on skin infections are some of my favorite episodes, in helping owners to understand why animals get skin infections and how we approach them. So I am thrilled to have you back, to talk about this complicated disease. Why don’t you give a little bit of background about yourself?
[00:01:57] Dr. Webb: My name is Alicia Webb Milum, and I’m a board certified veterinary dermatologist. As Dr. Lancellotti said, my primary practice location is in Oklahoma City, but I have locations in Tulsa, Oklahoma, as well as northwest Arkansas. I started my journey as a primary care veterinarian in Oklahoma city, so I have seen a lot of things that family care veterinarian see. But I decided that skin disease was really where my passion was, and I learned quickly that I really wanted to know more and become an expert in my field. Then, I pursued a residency with the animal dermatology group at Tustin, California (where we met) and now I am a dermatologist.
[00:02:35] Dr. Lancellotti: You and I going through residency together was probably some of my favorite years of my career. And I still refer to you and all of our resident mates as resident mates, even though we are long out of our residencies.
[00:02:46] Dr. Webb: Same! Forever and always.
Hopeless and Desperate for Help with Piper
[00:02:49] Dr. Lancellotti: So when you think about this particular disease, pemphigus foliaceous, do you have a certain patient that comes to mind?
[00:02:56] Dr. Webb: Yeah. This is actually a condition, as you mentioned, that we see fairly commonly. This is a disease that I see probably on a weekly basis. There are so many cases that come to mind, but one, in particular, is a dog named Piper. Piper is such a wonderful dog. She’s a great dog at heart, but when I first met her, she was really difficult to manage. She’s a large breed dog who was very itchy and painful, and this resulted in her being pretty agitated. And it was really impossible to get a good examination of Piper because she was really a bite risk because she was feeling so crummy. Her veterinarian had previously tried lots of therapies, but with no improvement. So with the owners hopeless and desperate, their veterinarian sent them to me for a second opinion, to try to get this girl some relief.
[00:03:42] Dr. Lancellotti: And you sent me some really nice pictures of Piper to see what Piper was looking like on her first visit with you. We’ll go through how you diagnosed what was going on with her and the treatments. There are some great pictures from after, as well, and how cute she’s looking.
What is Pemphigus Foliaceous
Dr. Lancellotti: Before we dive into that, let’s talk a little bit about what exactly pemphigus foliaceous is. Can you shrink our audience down, like Ms. Frizzle on the magic school bus, and talk about what’s happening within the skin during this disease process?
[00:04:20] Dr. Webb: Yes, I would love to. To understand pemphigus foliaceous (which is a mouthful, so we’ll call it PF), it’s important to understand that the skin is an organism with multiple sheets of cells, in different layers, with slightly different functions. These cells are held together by a structure called a desmosome, which is essentially glue holding the skin cells next to their neighbor. Pemphigus foliaceus is an autoimmune disease in which the immune system attacks those desmosomes, or that glue, and thus those cells in the skin lose their connection with their neighbors. In pemphigus foliaceus specifically, this is happening on the most superficial areas of the skin called the superficial epidermis. When this happens, we see pustules develop and the animals can be really itchy and sometimes painful. And these pustules that develop are really fragile, so what we can see is crusting with pretty significant tender sores underneath.
[00:05:13] Dr. Lancellotti: Yeah. These animals, oftentimes, are really uncomfortable. Some of our allergic animals are certainly very itchy and it can be miserable from their allergies, but these animals are actually feeling very unwell, and these pustules that they develop can be really painful as well, so it’s important for us to figure out what’s going on with them.
Pemphigus Foliaceous in Dogs and Cats
Dr. Lancellotti: If a pet has PF, what might the owner notice? What are some of those changes that occur to the skin? And is there a difference between the different species? Is there something that occurs in dogs that may not occur in cats, and vice versa?
[00:05:48] Dr. Webb: As I mentioned before, the biggest sign of pemphigus foliaceus in both dogs and cats is crusting, but they can do things a little bit differently. The crusting can primarily affect the face or be more generalized or all over the body, affecting areas like the ears or the paw pads in the trunk. Cats, in particular, really like to develop crusting around their claw folds. These guys, again, can be super itchy, painful, or both, and sometimes they can feel badly as well. They can have a fever. They can have their appetite be a little bit off. They’re generally feeling pretty badly, which is what prompts the owners to take them to a veterinarian.
[00:06:22] Dr. Lancellotti: And this is tough. A lot of times, we can see crusts on the body from other disease processes. Just infection from things like allergies or hormonal diseases can cause crusting too. The difference with these guys is that the crust doesn’t typically have a lot of bacteria associated with it. It’s just lots and lots of inflammation. And you mentioned the crusting around the claw folds – cats can definitely get a lot of disease by their claws. We’ve got some good pictures, on the website, where you can see how affected those claws can be, in those cats with PF. Their faces can get very crusty as a result of that. So we talked about those primary lesions, but a lot of times, those pustules are going to pop, forming a crust before the owner ever has a chance to see them.
Testing for Pemphigus Foliaceous in Dogs and Cats
Dr. Lancellotti: If we have these animals come into our clinic and they’re not feeling well, where do you typically start in terms of testing? What are you looking for on your physical exam?
[00:07:23] Dr. Webb: In my physical examination, I’m immediately looking for patterns. Again, I’m looking for whether I see pustules and crusts, and whether they’re isolated or symmetrical. But as you mentioned, these things are not specific for any one disease. My favorite test (and I think it’s a favorite test amongst a lot of veterinary dermatologists) is a really simple test called cytology. In cytology, I’m taking a simple glass slide and collecting a sample of skin cells from right underneath one of those crusts. If I get lucky and I find a pustule, I’m going to rupture it and take a sample from that as well. But I take that glass slide, I stain it, and I’m looking under the microscope to see what cells are involved. Basically, I want to know what my players are. In cases of infection, I’m going to see one thing, which is typically a cell type called neutrophils and bacteria, but in pemphigus foliaceus, I’m usually going to see neutrophils, but they’re going to look a little bit differently. The really big key that I might be dealing with pemphigus is presence of a cell called an acantholytic cell, or an acantholytic keratinocyte. Basically, acantholytic cells are prematurely released cells from the epidermis. Those acantholytic cells should not be released yet (still in the skin), but we find them in the crusts.
[00:08:39] Dr. Lancellotti: Yeah, acantholytic cells are definitely something that I look for when I suspect that animals might have PF. I always describe them like fried egg-looking cells. They’re darkly staining, they’ve got this much darker center, so they look like fried eggs. They’re going to have lots of neutrophils around their border because those neutrophils (immune cells) are attacking those cells. These are really immature skin cells, which should be at the very lower layer of the skin, not ready to be exfoliated, like our older dead skin cells that we typically see on the surface of the skin. So finding these is really unusual on cytology.
Biopsy for Testing for Pemphigus Foliaceous in Dogs and Cats
[00:09:22] Dr. Webb: While seeing acantholytic cells can spike our suspicion of pemphigus, there are things that can occasionally cause these as well. So the next step is a biopsy and histopathology. I also typically want to do lab work on these dogs because they’re feeling kind of crummy. And many of the medications that I might need to use to help them feel better can have side effects that need to be monitored closely, so it’s really important to know our starting point.
[00:09:46] Dr. Lancellotti: Absolutely. I agree. That blood work is super helpful, in knowing what we’re dealing with at that moment, but then also monitoring response to treatment. A lot of these guys have a significant increase in a lot of their white blood cells because their immune system is just on high alert and working overtime, with this particular condition. You talked a little bit about a biopsy. Let’s very briefly go through what is involved in a biopsy and that whole process, so that the owner can understand what’s happening with their pet.
[00:10:20] Dr. Webb: Sure. A lot of times when we say ‘biopsies,’ owners get freaked out. They think that it sounds really invasive, and that’s certainly understandable. Typically, in dermatology, when we’re doing a biopsy, we’re using really small punch biopsy. The typical size of a biopsy is about 6 millimeters. Sometimes, it’s a little bit more or a little bit less. These animals are usually sedated for comfort, and then we’re basically using that punch biopsy as a cookie cutter. We’re cutting out a small sample of those lesions that we think will represent the underlying disease process, so that a pathologist can look at those slides in cross section and confirm, or give us more information about what actually might be going on.
[00:11:04]Dr. Lancellotti: Yeah. I like to tell owners that it’s scalpel blade in the shape of a circle, about the size of a pencil eraser. Usually, we’re going to take about 3-4 samples, so that the pathologist has a couple of different areas of the skin to evaluate, to make sure that we have a really good confirmation of our diagnosis. It’s a really simple procedure, usually very quick for us to perform, and not something that’s going to be terribly painful. Especially, because we’re going to be using some local anesthetic, underneath the surface of the skin, to numb the area where we’re taking our little tissue samples. Usually, there’s only one or two sutures to close the area where we took our incision. It’s something that we do on a very regular basis, in our dermatology practice, and not something that poses significant risk to most animals that have a suspicion of Pemphigus. But that’s really helpful in getting us a diagnosis of what’s going on
Medications for Pemphigus Foliaceous in Dogs and Cats
Dr. Lancellotti: Once we have a diagnosis, we need to come up with a treatment plan. I want to very briefly go over some of the treatment options that are available for these animals.
[00:12:06] Dr. Webb: Yeah. So there’s definitely no one way to approach a patient with Pemphigus. In general, it’s treated by immunosuppression. However, there are so many factors that influence my decision to use a particular drug or drug combination, including the size of the patient, which can affect costs and the dosage forms available, as well as pre existing conditions like heart, liver, or kidney disease. Steroids, like prednisone, are usually needed to put out the fire early on. However, we all know that steroids can have pretty significant side effects, both in the short term and the long term. In the short term, these include drinking a lot of water, resulting in urinating frequently and sometimes inappropriately, as well as excessive hunger, which can occasionally lead to destructive or aggressive behavior. Steroids can also come with risk of GI ulceration or sometimes making a patient with heart disease get worse. I almost always add in another drug, to spare the dosage of steroids needed to control this patient’s symptoms, and hopefully side effects long term.
[00:13:07] Dr. Lancellotti: Yeah, and that’s really important because, with this particular disease, the immune system has such a long memory, and it remembers that those desmosomes are something that it wants to attack. If we have animals on steroids for a very long time, they are going to experience side effects that may affect their quality of or the length of their life. Using those steroid sparing medications will be very helpful for us in the longterm management of this disease, while allowing us to minimize the longterm side effects and risks of our medications. Tell me about some of the steroid sparing drugs that you might reach for.
[00:13:51] Dr. Webb: Which drug I’d choose is based on several factors. For dogs, these might include a medication called mycophenolate. More often, I’m reaching for oclacitinib (Apoquel) off label. But in autoimmune diseases, I’m using this off label at considerably higher doses than I would use for allergies, as well as a medication called pentoxyphylline, and in really severe cases, azathioprine. For cats, I might reach for cyclosporine, as a first line drug, but I might also reach for a medication called chlorambucil, if the pet is not getting better. It’s important to understand that each of these drugs does something a little bit differently, they can take different times to reach full effect, and they can often be used together, to attempt to minimize the risks and side effects of any particular drug, over the long run. I am really commonly using two to three drugs for a particular patient.
[00:14:41] Dr. Lancellotti: Yeah, I agree. This is not a disease where I usually have success with just one medication. And I think about all of the patients with pemphigus that I’ve treated or am currently treating, and I don’t think I have two animals that are on an identical treatment plan. Every animal responds a little bit differently, and each animal has their own set of risk factors, in terms of other underlying conditions that we maybe need to keep in consideration. It’s really important, when we’re selecting a treatment plan, that the person prescribing the medication has a good understanding of your pet, and a good understanding of how to use these medications. This is a disease, in particular, that if there is a veterinary dermatologist in your region, and you can consult with them, that would be great opportunity to find somebody who is highly skilled at managing this disease and using these medications in combination.
[00:15:41] Dr. Webb: I agree. And one more thing to add- be sure that the veterinarian prescribing these medications knows what you’re giving to your pet. Some of these medications can have pretty significant drug interactions, so it’s important that we understand all of the various things that your pet might be exposed to.
What to Expect with Pemphigus Foliaceous in Dogs and Cats
[00:15:57] Dr. Lancellotti: So When I’m treating this disease, one of the first things that I want to do is get the animal into remission. Let’s talk a little bit about the stages of treating these pets.
[00:16:09] Dr. Webb: Yeah, this is really important. This is not a “set it and forget it” type disease, or else we would wind up with a lot of side effects, from medications, that may be worse than the disease itself. The first stage of treating pemphigus is getting the pet into remission (putting out the fire). This is usually when we’re using the highest doses of drugs, especially prednisone or other steroids. How quickly this happens is very case dependent. We’ll have some pets respond rapidly while others can be quite a bit more challenging. But once we get the pet into remission, the real tightrope walk begins, as we gradually try to reduce drugs to the lowest effective dose, starting with whatever drug is the most problematic for that pet. Occasionally, we reach setbacks, as we reduce or change drugs, and it’s very much a dance that requires skill on the part of the doctor, and often patience on the part of the pet owner.
[00:16:59] Dr. Lancellotti: Yeah, I agree. It’s not something that is going to be very easy, like “Okay, this is what’s going to happen and your pet is going to be fine.” Here, we talk about monitoring for relapse and having the owner watch the pet really closely, as we try to pull back on some of those medications, to help to reduce the risk of side effects. It’s important to have that open communication with your veterinarian, so that they can be aware of anything that you’re seeing, as you’re making dose adjustments to that medication plan. One of the things that also plays a role, in terms of how much of a chance the animal has to be able to pull back on that medication, is whether or not there was a trigger for pemphigus. Some animals can have this autoimmune disease be triggered by things like vaccines or certain medications. Other times, we just don’t know why it happens (idiopathic). If it’s a case where the animal took a medication for something that was going on, and that medication caused a really rare reaction, as long as that animal doesn’t get that medication again, there’s a good chance that we can pull back quite a bit. Whereas, with those animals that have idiopathic (where we don’t know), or maybe there’s some other disease process that’s triggering the immune system to be overactive, those animals are a little bit more challenging to pull back on their medications.
[00:18:25] Dr. Webb: Yes, that’s certainly true. And unfortunately, we don’t have an easy way of knowing ‘who’s who,’ in all cases.
What is the Prognosis for Pemphigus Foliaceous in Dogs and Cats?
[00:18:31] Dr. Lancellotti: In terms of prognosis, what do you tell owners, as far as what to expect with treatment of this disease?
[00:18:38] Dr. Webb: We’re able to help the majority of patients with pemphigus live long and fulfilling lives, but unfortunately, not all. One retrospective study reported that 52 percent of dogs achieved complete early remission, and 35 percent achieved partial remission. Unfortunately, 13 percent of dogs were euthanized, due to treatment failure, drug side effects, or perceived poor quality of life. I feel like the majority of pets are able to be maintained, with a reasonable drug protocol, if we have a committed owner.
[00:19:08] Dr. Lancellotti: Yeah, I think that commitment is one of the most important aspects of this disease. This is not something where you’re going to give 1 pill and things are going to be finished. It really does require ongoing care and communication, as part of a team effort to help the pet.
[00:19:22] Dr. Webb: The other thing to note is that, as you mentioned, most patients need to receive treatment for the rest of their lives, but the long term goal is the lowest effective dose of the drug combination, to keep that particular patient free of symptoms, and with the least amount of drug side effects and costs.
[00:19:36] Dr. Lancellotti: Yeah. This is something that we definitely can manage.
Piper's Pemphigus Foliaceous is in Remission!
Dr. Lancellotti: We’ve got plenty of patients, that you and I have treated, who have done really well, including our lovely pet from the beginning of the episode. We’ve got some really nice “before and after” pictures of Piper. What are some of the big takeaway points that you’d like pet owners to remember when we think about PF?
[00:20:14] Dr. Webb: So PF can be a scary and very dramatic disease, but in most cases, it’s manageable. There are so many options that can be used in so many different combinations, so it’s important that you have a good working relationship with your veterinarian and that you understand that it can be a journey. In Piper’s case, she has done so well with treatment. She’s now managed with fairly low doses of Apoquel, Mycophenolate, and Prednisone. She now gladly also allows pets and rewards “good girl” praise with a tail wag. Pets like Piper and her people really drive home the reason that we do this every day. It is absolutely a privilege.
[00:20:47] Dr. Lancellotti: Oh, I agree a hundred percent. These dogs feel so crummy, when they first come in, for their initial consults. And when they come in for those recheck exams, and they’re finally in remission, it’s like dealing with a completely different dog. It brings tears to both my eyes and to my owners’ eyes. They have their pets back. It’s really awesome.
[00:21:06] Dr. Webb: It’s one of my favorite things.
Come Learn with Dr. Webb Milum!
[00:21:08] Dr. Lancellotti: Do you have anything that you would like to talk about, in terms of some upcoming events that you might be involved with?
[00:21:15] Dr. Webb: I would. So veterinarians, if you are listening here today, and want to learn more about pemphigus foliaceous and other autoimmune skin diseases, please consider joining in San Juan, Puerto Rico in January 2025 with Vet Vacation CE.
[00:21:29] Dr. Lancellotti: Oh, that’s so exciting. Puerto Rico. And you mentioned Vet Vacation CE- I’m actually doing a seminar with them in Glacier National Park in June of 2025, so I’m looking forward to that. I’ll be talking about lots of derm topics there, as well.
Scratching the Itch
Dr. Lancellotti: So at the end of every episode, we end with a segment called Scratching The Itch. This segment highlights something- either a human interest story, a product, a website- whatever it is that provides relief or just makes you feel good. Hence, scratching the itch. Do you have a ‘scratching the itch’ for our listeners today?
[00:22:03] Dr. Webb: Yes. Today, I would like to give a shout out a local animal rescue organization called Free To Live, and especially highlight three people from the organization- Reagan, Casey and Wyatt. At Redbud Animal Dermatology, we do a lot of work with Free To Live, helping the animals in their care with skin and ear disease. And I am constantly amazed at the capacity of Reagan, Casey and Wyatt for boundless love and compassion. Caring for animals, in general, is a lot of work, and caring for animals with chronic diseases takes an extra level of dedication. These guys rescue and care for animals in all kinds of situations, and they can use all of the support that they can get. They are heroes.
[00:22:48] Dr. Lancellotti: That’s great. Check that out and support the wonderful work that Reagan, Casey, and Wyatt are doing, that would be fantastic. We appreciate any support our listeners can give. Thank you so much for coming on the show and talking about pemphigus foliaceous, today. This is certainly going to be helpful for me, in the clinic treating my patients, and I hope it’s helpful for pet owners out there who are going through something very similar.
[00:23:16] Dr. Webb: Thank you for having me, Dr. Lancellotti. I’m always happy to be here.
[00:23:20] Dr. Lancellotti: And for all of our listeners, I look forward to your next visit with Your Vet Wants You to Know.
