Welcome to today's webinar on the topic of unusual dermatology cases, presentations you won't forget. My name is John Hardy and I'm an RCVS and European specialist in veterinary dermatology. And I work at Lumbury Park Veterinary Specialists in Oldtonhampshire.
So the plan for this talk over the next 50 minutes or so is to present 5 conditions with quite distinctive presentations. Now all of these conditions are quite rare, and you may not have seen them before, but I just hope by introducing them today you'll just be that bit better prepared if you do encounter them in the future. So the aims for the talk are to be able to recognise these conditions, describe the skin lesions with confidence.
Consider other differential diagnoses. And then select appropriate diagnostic tests. And then we also want to be aware of some treatment options for these conditions.
Now it's just worth saying within the sort of available time for this talk, I don't have time to go into huge amounts of detail about the treatment options for each condition, but hopefully we'll go and we'll present an overview so you've got the general options. So the first condition I wanted to talk about is eosinophilic pharynculosis of the face. This is also known as canine aosinophilic folliculitis and phylosis.
This is an uncommon disease that has a very acute onset, which is one of the really defining features of this condition. This is one of the very few conditions that really progression is seen within hours, so you may have a fairly normal unaffected dog, and then later that day they've got a really quite severe skin problem. The ATO pathogenesis is not fully known, but there are possible links to arthropod and insect bites.
This condition usually affects the face, especially the bridge of the nose and around the muzzle. But we can also sometimes see other areas affected like around the eyes and on the ear pinny. And then also rarely other body sites as well.
The classic clinical signs include papules and nodules, which are, which can be defined as solid elevations in the skin, less than 1 centimetre in diameter if they're papules or greater than 1 centimetre in diameter to define a nodule. Crusts Which is the term for dried exudate. And then oozing exudated lesions as well.
We can also see edoema and haemorrhage. So if you look at this dog here, in the photo, this is a dog that I saw some years ago at my previous job in the West Midlands. This was a young Labrador, who presented with this really quite severe, acute onset, exudative and hemorrhagic, lesion over the bridge of the nose.
Now we don't really have discrete papules and nodules here. This has become this is all sort of coalesced into what we could describe as a plaque, which is a raised lesion that is wider than it is high. But you can certainly see there's surface crusting and areas of ulceration and and exudate.
Despite the severity of the skin lesions with this condition, many dogs actually aren't particularly pruritic or painful. But you can see, hopefully see in this picture that this dog is wearing a buster collar because I think when they get to this level of severity, you could imagine that this dog might be wanting to scratch or rub its nose. Systemic signs are quite variable and, and if they are present, they're normally quite vague.
The dogs can be just sort of lethargic, with it, but they're not normally, otherwise unwell. We can see osinophilia on blood work, but really other findings on blood testing would be fairly nonspecific. And another distinctive feature of this condition is that we tend to see it mainly in young large breed dogs.
And this might be because these dogs are, by their nature, inquisitive. They haven't particularly learned about the world that much at this at their early age, and they're perhaps more likely to go and interact with arthropod and insects and, and, and, and have a direct interaction that way. Despite the severity of this condition, recurrences after treatment are normally rare.
It's possibly just because these dogs eventually learn to not go interacting with these insects or arthropods. It might just be that that sort of interaction is very rare in the first place, but we don't seem to get dogs having this multiple times. This condition is highly responsive to glucocorticoids.
And it is really important to try and identify this problem and treat it as early as possible, because when you've got lesions as severe as this dog has and because of the process of phunculosis, which by its definition means breaking a part of the hair follicles as part of the inflammatory process, we can see scarring as a sequelae of that. So we need to try and address this and treat it as soon as possible. Here's another dog that was seen some years ago.
This was at the Royal Veterinary College. So this dog, you can also see. Has quite moist exudative lesions over the bridge of the nose, but one of the things you can see in the in this photo and the previous photo is that it's quite well demarcated in the sense that it does not progress onto the nasal planum.
The sort of cobblestone architecture of the nasal planum is normal. There's no loss of pigment. This is affecting the head, skin, and the bridge of the nose.
This dog also had lesions at other sites as well. You can see in the photo on the left that there's an ulcerated crusted lesion above the right eye as well. And this just shows the other lesions on this particular dog.
In the photo on the left, we've got some erythematous and crusted papular lesions down by the hop, and then this dog also had a few similar lesions over the dorsal paws. This would be one of the more severe cases that I'd I've advised on in the past. This was sent in to me by a veterinary surgeon in practise.
Very well demarcated, very moist, very severe skin reaction. And you can obviously understand that you might have quite an upset and worried owner with a presentation like this, where this dog may have been completely normal the day before and now has a really quite severe and looking skin lesion over the bridge of the nose here. And again, a bit like the previous photos I showed you, you can see just how well demarcated this is, even though this is a very severe dermatosis.
You can see that the nasal planum is not affected. There's this dog actually has an extremely healthy looking nasal planum, normal pigmentation, normal nasal architecture. And that can be a clue that actually you're not dealing with something like an autoimmune disease in this case.
The lesions in this dog very raised, you get the impression this could have started off as papcules that have sort of coalesced into this large moist plaque of inflammatory tissue. So what are the differential diagnoses for this condition? Well, You could get a deep bacterial infection presenting in a similar way to this, although it's worth saying that bacterial infections are actually quite rare on the face of dogs.
Dommatophytosis is also possible. We do get dermatophytosis affecting the face of dogs, particularly terrier type breeds, young dogs that have inquisitive natures, putting their noses into wild animal burrows and things like that. They can develop sylvatic dermatophytosis around the face.
Both that and the deep bacterial infection wouldn't tend to present so acutely. The one of the one of the things that's really quite distinctive about a sinophilic ronchiosis of the face is just how quickly this problem comes on, literally over hours. And it's the same with demodecosis really.
Demidiosis obviously can be found around the face, particularly of young dogs, but the speed of onset wouldn't be typical for demidiosis. And then a really common thing that people might think of when they see dogs presenting with lesions like this would be some sort of facially orientated autoimmune skin disease. And that's understandable because this is a severe problem.
It's come on quite quickly. But there are some things that just don't really fit so well, so autoimmune disease generally is seen probably in middle aged to older dogs. This is tends to be seen in young dogs.
Autoimmune diseases generally don't come on this quickly either. They tend to have a more protracted clinical course. This really is just over hours and you have a normal dog suddenly developing this really, really severe skin lesion.
And the other thing, like I said already, is that the nasal planum and the other areas around the muccocutaneous junctions are actually not affected in this condition, which we would sometimes see with autoimmune disease as well. So what are the appropriate diagnostic tests for a dog presenting with a lesion like this? Cytology is probably the number one test to do initially.
And that's to help identify if there's a component of bacterial infection. And because this lesion, this moist plaque is so moist, it probably lends itself quite well to something like an impression smear. So you could get a glass slide and impress that directly onto the nose, let that air dry, and then stain that and look and look for signs of bacterial infection.
Which in an uncomplicated case of sinophilic culosis of the face, there just won't be any bacteria there. What you will typically see is huge numbers of osinophils. And this photo just down at the bottom here just shows you an osinophil.
We've got these osinophilic pink coloured granules within the cytoplasm of these inflammatory cells. Just because of the nature of the lesion being very ulcerated, we'll sometimes see some neutrophils obviously as well as a component of that, but sinophils predominate. We probably also perform some hair plucks and skin scrapes from around this lesion to rule out demitocosis, although many dogs these days are routinely treated with the oralisoxazolines, which would cover for this anyway.
You may want to perform a complete blood count looking for a sinophilia, which would be supportive but on its own not diagnostic. You may want to form a lamp and dematify culture. But I, I guess that's in brackets just because that might not necessarily need to be done because you might already have a pretty good idea that this is actually looking more like an osinophilic phunculosis to the face.
But it wouldn't be wrong to submit for that to be thorough. Biopsy can also be performed in these cases. This would be the sort of lesion that you probably would need to have a short general anaesthetic to biopsy because of the location on the face.
I think this would be quite a sensitive area to biopsy just under sedation. And on histopathology we will see marked aosinophilic mural, and luminal folliculitis and phunculosis. The mural refers to the fact that the osinophils are infiltrating into the walls of the hair follicles and also in the lumen as well into the actual where the hair shaft is in the hair follicle.
Pharunculosis refers to the breaking apart of the hair follicles because of the severity of the inflammation. And that reflects in how severe the skin lesions are as well. But do we have to do all these tests and do we have to biopsy these dogs?
Well, the answer to that is probably no. I, I think this is one of those sort of conditions where a clinical diagnosis can be made, and that's because. If you bring all the features of this condition together.
The very acute onset, the young otherwise healthy dog. The severe skin lesions restricted to the head, skin around the nose, the bridge of the nose, and cytology showing. Huge numbers of sinophils in the absence of infection that probably is enough to be able to make a clinical diagnosis and start treatment based on that information.
And another reason why a clinical diagnosis is helpful is because we do need to try and start treatment as soon as possible for these dogs. If you biopsy, obviously we've then got 345 days to wait before the report comes back, and that's delaying treatment in that time. So treatment options for this condition, well, This condition is very responsive to glucocorticoids, so we usually give something like prednisolone at 1 to 2 migs per gig.
Per day until clinical remission. And that's normally very effective, but it is important in these cases to use that sort of dose until clinical remission, which would need to be assessed by you, the clinician. So typically I might start this dog on that sort of dose of medication and then schedule some weekly rechecks to then be able to assess progress.
This wouldn't probably be the sort of case where you'd want to start that sort of dose and then use that for 3 days and then get the owner to start tapering because you really want this, this condition to be in remission before any attempt at dose tapering. The prognosis is very good though because after usually a few weeks, clinical remission is obtained and you can taper off that that prednisolone fairly quickly over a week or two, and most of these dogs don't have relapses and go on to do very well. I guess the main worry in terms of ongoing complications, I suppose, would be some persistent scarring that may be seen at the affected areas.
Because of the process of pharynculosis breaking those hair follicles open, it's difficult at the at the at the onset of treatment to really know how much alopecia and scarring will remain in the long run, but it's something that I do always or would always warn owners about. He's just some follow up pictures. This is the dog on the left here.
So this is after one week of prednisolone, at the, the, the 1 to 2 Migs per gig per day, dose. You can see quite a significant improvement here. There's obviously a lot, lot less .
Haemorrhage. The lesion is no longer raised, which is important, and we do still have a few little erythematous crusted papular lesions in the centre, so this would be the sort of point where I might just consider keeping that dose going for a little bit longer. And then this is the same dog after 2 weeks, and this is where I would probably judge clinical remission to be.
So really no real significant trust anymore. We obviously do have persistent alopecia at this stage, but it would be impossible to really know how much hair regrowth was going to happen over the coming weeks to months after that. But this would be the time when I would start to reduce the steroid down.
Here's the other dog that I showed you. This is the same dog. I think this photo was sent in by the owner, I think something like 3 to 4 weeks later, again you can see, complete remission of lesions.
We've got flat non-inflamed skin now. We do have some alopecia clearly and we also have some areas of likely post-inflammatory hyperpigmentation as well, but you can see that the lesions, the active lesions of this problem are very much under control now, and this can be taken off the steroids. So conclusions from this condition are this is an uncommon condition.
I mean, I, I've seen a number of these cases over the years, but not many. This is quite uncommon, but it is visually distinctive and taking everything all into consideration the presentation, the types of lesions, the severity, and the and the speed of onset, it is very distinctive. And as a result, diagnosis is usually straightforward, especially if you can find cytology demonstrating huge numbers of sinophils.
Early treatment is important. We need to try and avoid or minimise scarring, so we want to get these dogs onto prednisolone or similar as soon as possible. The prognosis is usually excellent though these dogs go on to live completely healthy normal lives and usually don't have any relapse in the future.
OK, moving on to the second condition. So this is vesicular cutaneous lupus erythematosis. So this is one of the types of cutaneous lupus erythematosis that I thought it'd be worth talking about today just because I think this one is quite a distinctive presentation that it's worth being aware of.
This is analogous to the humans subacute cutaneous leukhoseinatosis. There are chronic variants and acute variants as well. Now this particular variant predominantly affects sheepdogs and collies and collie crosses.
Usually coming on in middle aged older adults. And often with an onset in the summer months, and this links into the fact that lupus erythematosis has this link to UV exposure as part of its a pathogenesis. Lesions are usually found on the ventral abdomen, axillae, and groynes.
It has this sort of ventral distribution. We can also sometimes see lesions on the mucous membranes around the lips, and, the, the ear pinny too, but it's predominantly the ventral distribution in the, in the axili and ventral abdomen. Lesions consist of erythema progressing to ulceration and crusting.
We can hopefully make out in this photo, it's quite difficult to photo and this dog was not the easiest to photograph, but we can see areas of marked erythema in the groyne here and then we've actually in the axillary areas we've got more of these annular shaped sort of ring shaped areas of erythema and ulceration. Progressing to polycyclic lesions where they sort of these annular lesions merge and form unusual patterns, and even becoming sapiginous, which is almost snake-like in in distribution. Because this is an autoimmune condition, symmetry is often a feature.
So this problem is coming from within, so this would be something that affects both sides of the groyne, both axillae, and that can certainly raise your suspicions of, of, of a, of a sort of systemic process. These lesions can be painful, but they are not usually potic. So here's some more pictures here of another dog that I've seen in the past.
This is a little bit little bit less severe, but we've still got these annular areas of erythema with progressing to ulceration. This is the ventral abdomen of a collie. And this is a more severe case that I saw a year or so ago, much more severe ulceration, but again affecting the ventral abdomen in a symmetrical pattern.
This particular dog's got quite an extensive area of skin affected, but also quite a lot of sort of matted hair and surface exudate just because of how sore and exuberive these lesions were. And this dog wasn't heretic but really quite painful, so even just trying to examine this area was very painful for the dog. A few more pictures here on the left showing areas of erythema with some central ulceration and crusting.
And in the photo on the right just demonstrates that we can get areas of erosion and ulceration around the mucus cutaneous junctions as well. So what are the differentials for this sort of presentation? Well, We could certainly see microbial overgrowth or superficial bacterial infection presenting in a similar sort of way.
So areas of diffuse erythema in a groyne could quite easily be malaceded dermatitis, for example. Circular and multifocal patches of erythema and crusting and scaling in areas like the axill and groyne that could also be superficial spreading pioderma, for example, so we need to be wary that those common conditions could also be present as well. Eerythema multiforme is a new mediated hypersensitivity reaction that can also present in similar sorts of ways with circular areas of erythema and erosion.
Systemic lupus erythematosis could present in a similar way, although because that's a systemic variant of lupus, we would also expect to see other clinical signs involving other body sites. And in pemphigus vulgaris potentially could present in a similar sort of way, this is a deeper variant of pemphigus than the more common pemphigus foliaceous. Penthigus vulgaris tends to affect areas around the mucocutaneous junctions and inside the mouth and areas like the foot paths, and it's extremely rare.
So in terms of diagnostic workup for this sort of presentation, cytology would be probably the number one and first test to consider doing. You could do an impression smear, but because these lesions might not be quite so moist as the previous case I showed you with the oozing lesions on the nose, this might lend itself better to something like a tape impression, and then you could then stain that and analyse that and look for evidence of malashesia or bacterial infection to support or discount infection as a cause. Obviously in some of these cases you can get bacterial infection as a secondary thing, so it's sometimes necessary to identify that and then address the bacterial aspect first of all, and then reassess the dog to to see what residual lesions there are.
But ultimately, if this, if there is no element of bacterial or or or or other type of infective process there, or if treatment for bacterial infection has been performed and there's still remaining significant lesions, then biopsy is going to be needed. Histopathology demonstrates a elvich lymphocyte mediated interface dermatitis. Interface dermatitis refers to the pathology present and targeting the junction or the interface between the epidermis and the dermis.
And classically we're also seeing basal cell apoptosis with this condition as well, which is basically the basal layer or the the deepest layer of the epidermis showing areas or cells demonstrating apoptosis. There will also sometimes be subepidermal vesiculation, which means areas of fluid filled lesions just underneath the layer of the epidermis. And a linoid band of inflammation in the dermis, which is just this band of inflammatory cells accumulating in the dermis underneath where the process is targeting the interface.
These are the sorts of features that pathologist will see and then report back to you. In terms of treatment, well, this is the type of presentation that is quite variable in its response to therapy. And it, you know, some cases can be quite mild, some are more severe, and certainly in the cases that I've seen over the years, some of them are much more difficult to control than others.
We would often start with corticosteroids, so again, something like prednisolone at 1 to 2 mg per gig per day would often be started. And that would be normally given every day and then with regular rechecks and follow up to assess whether clinical remission had been obtained. And if it had, you would then normally start to taper that dose down to the lowest possible level that maintained remission.
But usually most of the dogs with this condition need to stay on some level of therapy long term. It's often necessary to add in 2nd agents, 2 immunosuppressive drugs. There's a report of mycophenolate motel being used for vesicular cutaneous lupus.
And also the calcium neuron inhibitors like cyclosporin. And in the past I've certainly had to use cyclosporin in conjunction with Prednisolone to control these cases. With variable efficacy.
It's also important to consider UV exposure as part of the ongoing management of these cases. Just because it links into the ATO pathogenesis. So we'd want to try and avoid these animals being exposed to high UV and avoid the air at the times of the day in the summer months when sun exposure was at its highest.
And we've probably all seen dogs that like to lie on their backs out on the decking and sunbathe. That would be something to definitely avoid in a dog with this condition. The prognosis is really quite guarded because some of them do well, some of them are much more difficult to control.
So the conclusions for BCLE are that this is a distinctive presentation causing unusual patterns of erythema and ulceration in the axillian groyne of sheepdogs, pollies, and their crosses. And that's the sort of really thing, the thing to really remember. It's, sheepdogs, collies and their crosses with that ventral distribution, in a symmetrical way.
Remember that the mucocutaneous junctions can also be affected as well. And we will need a biopsy to diagnose this condition. And in general, whenever biopsying any of these sorts of immune mediated conditions, you want to try and avoid areas that are completely ulcerated because you do need ideally an intact epidermis.
To so that the pathologist can see that interface process occurring. So you want to ideally pick areas that are erythematous but do have an intact epidermis, so not direct, don't, don't biopsy directly from ulcers. Treatment can be difficult and the prognosis is guarded, but obviously if you can identify these cases quickly without the lesions progressing too severely, then getting them under control may well be a bit easier.
OK, so the next condition is proliferative arteritiss of the nasal philtre. Now this is a rare, but very distinctive vascular disease. And it also goes by the name of dermal arthritis of the nasal filtrum.
This is seen in various usually large breed dogs, and the photo I've shown you a case of that I saw is in a pointer. But in the initial case reports of this condition, St. Bernard's appeared predisposed.
This tends to affect young adult dogs. And we have this really striking alteration on the nasal philtre. With a sort of oval to linear area of ulceration.
And one of the really distinctive features of this is that we can get intermittent variable haemorrhage from these areas even to the point of actually having sort of arterial bleeding from these sites. So we've seen cases in the past that are presented as emergencies to internal medicine teams in the past, and actually they've ended up having a nasal condition like this. The aetiology of this condition is unknown.
But it's likely that there's genetic factors because we do tend to see this in larger breed dogs in Saint Bernard's predisposed, but no one really knows. Here's another dog that I saw with this condition at my previous job some years ago. You can see the really well demarcated deep ulceration on the nasal filum of this dog.
Now you'll also just see, and you may have seen in the previous photo as well, that there are these little small linear fissures just on the nasal. Playing them as well, which we'll talk about in a minute. So what are the differential diagnoses?
Well, There aren't really, to my knowledge, really this is one of those sort of conditions that has a really distinctive presentation, and I'm not really aware of any other condition that would cause such well demarcated ulceration to the nasal philtre of a dog. If you did have lesions at other sites, then in theory, you could be dealing with more of a widespread or generalised vasculitis or vasculopathy. But classically in, in, in this particular condition, these dogs don't have lesions at any other body site.
At all, so they're otherwise well and healthy, and we don't know what triggers this problem. Just point out that you can see these little linear fissures again on the nasal plan of this dog. In terms of diagnostic tests and diagnosing this condition, well, you would need biopsy to try and gain more information really, and that can demonstrate subendothelial internal proliferation.
Of spindle cells in the deep dermal arteries and arterioles. And sometimes a true areritis, i.e.
Inflammatory cells within the walls of the blood vessels, the arteries, is sometimes seen, but not always. But this would be the sort of condition where a clinical diagnosis is often made. And that's partly because there aren't really any other differential diagnoses.
And it's so visually distinctive, but it's also because biopsying these dogs is not particularly appealing. It's really not an area that you would many people would feel very comfortable biopsying and bearing in mind some of these dogs have come in with active arterial bleeding from these lesions anyway, the thought of actually then trying to take more tissue from them, it doesn't necessarily fill you with a lot of joy. So what are the treatment options for these dogs?
Well, a number of things have been tried, and generally when lots of things have been tried, you get the impression that there's nothing that's particularly perfect in these situations. You can use systemic prednisone, that would probably need to be used at doses of around sort of 11 to 2 migs per gig per day again to try and get the condition under control. But we'll often actually try tacrolimus cream in in these cases.
So tacrolimus is a topical calcineurin inhibitor, it's not licenced for dogs, it's a human product. But the advantage of using something like tacrolimus is that we're just applying it to the sites that are affected. Remember, these dogs don't have lesions that other body sites.
So therefore, the appeal of that is that we're not medicating our dog's whole body for what is quite a localised problem. Doxycycline and niacinamide, that sort of combination of a tetracycline and niacinamide is quite an old combination with mild anti-inflammatory properties that have been used for numerous new mediated conditions over the years. We don't tend to use that so much these days, just from a prudent use of antimicrobial point of view, we don't really want to be using an antibiotic for ongoing use if there isn't a bacterial component.
Pentoxyhyle is another drug that has mild anti-inflammatory properties and can be used in, it's often used in vascular disorders that can also be tried, that's a usually a fairly well tolerated oral medication for dogs. And surgical resection is even an option, in some of these cases and has been helpful in some to try and actually, remove some of this affective tissue, but I personally haven't ever had to send a dog for that. The prognosis is variable.
And most require long term management. But this is the outcome of one of the dogs that I saw. So this is the dog on the left here at initial presentation, and then on the right you can see quite significant improvement.
This dog went on to tacrolimus cream at 0.1%. So that goes by the trade name of protopic cream often in humans.
So this owner was applying the tacrolimus twice a day to these lesions initially. And also applied the cream onto these little fissures on the nasal plane as well. Now obviously you can see that this nose on the right doesn't look completely normal, so there's a complete lack of pigmentation at the nasal philtre, but it's no longer erythematous or ulcerated.
So this was actually judged to be in remission at this point and then we basically. Reduce the frequency of tacroliness down to the lowest possible level, and I think from my memory I think we were able to get away with using it quite relatively sparingly 2 or 3 times a week. So the conclusions of this condition.
Is that proliferative arthritis of the nasal philtrum is a striking and visually distinctive skin disorder restricted to the nasal philtrum of dogs. It can present as an emergency though, so it can be quite an emotionally charged situation with arterial bleeding in an otherwise healthy dog, so it can come as quite a shock to owners when this happens. There aren't really any other differential diagnoses for this very distinctive condition.
Treatment is usually long term, but in some cases it can be managed with the something like tacrolimus cream, then the ongoing management of problem is not too onerous. Now we'll just quickly mention nasal aar arteryopathy. So there was a recent report just a few months ago really published in Bey dermatology of this condition in 14 German shepherd dogs with fissures on the nasal alar folds.
And these dogs had episodes of arterial bleeding, and lesions had histology very, very much like the nasal arthritis condition. Treatment options were similar and for that condition, but in that particular case series, they actually found a punch biopsy, so actually biopsying these fissures were sometimes curative in these cases. So I just mention that because this is likely to be a similar process to the the, the, the, the, the arteropathy, and arthritis of the nasal philtrum.
And the cases that I've seen of the with the iltrum affected have also had these little fissures on their nasal planums as well, and it's quite likely to be connected, in some way. OK, so another condition I wanted just to briefly mention today is necrotizing otitis externna of kittens. Now this is an extremely rare condition, but it's highly characteristic.
So this was initially reported in cats less than one year of age, hence the name necrotizing O type externa of kittens. But since its initial description, we have had reports of it affecting older cats too, sort of between the ages of 3 to 5 years, so it probably isn't correct just to, to, to call it, exercising a type 6 turn of kittens. It has an unknown aetiology and despite investigations there have been no proven links to infectious agents and it's actually thought to be an immune mediated aetiology.
Possibly similar to erythema multiforme, and that's because the histology of these cases has similar features to erythema multiforme with an interface dermatitis. In this condition, we have very well demarcated erythematous plaques with thick crusting on the medial pinny and extending into the entrance to the ear canals. And because this is coming from within, this is a systemic process, this is something that you'd expect to affect both ears.
And then rarely we can get similar lesions in the prericular skin as well. This has an acute onset. With lesions in annular or supigynous patterns.
And that crusting can progress to alteration. And as I mentioned, symmetry is usually present affecting both ears because this is a systemic process. Despite the severity of the skin lesions, the crusting and alteration, pruritis and pain is usually quite variable, and some cats don't seem to be particularly affected by the problem.
And interestingly, these crusted lesions in the ears of cats have been reported to often digress spontaneously. By 12 to 24 months. Which is quite a long time.
But we know that some can also persist and therefore that's why treatment is often. So what are the differential diagnoses for an otherwise well, usually young cat presenting with symmetrical crusting plaques and erosions in the ears? Well, there aren't really many other differentials for that.
It's really quite a distinctive presentation. If lesions were to extend beyond the ear canals, it would certainly be worth considering dermatophytosis, so you may need to performing wood lamp examination and dermatified culture. Penmphigus foliaceous would also be on the list if that happened.
So the photo down both of these photos show cats with pemphigus foliacious. But neither of these cats had lesions restricted to the ear canals. They have lesions in other classic areas of pemphigus like the claw folds around the nipples, and also around the, the, the nasal plane and bridge of the nose.
Bowennoid in situ carcinoma or BISC is a multi multifocal form of squamous cell carcinoma in situ, and that could also cause similar lesions if they extended out onto the other areas around the head. But really with this very, very distinctive presentation of acute onset crusting within the ears of otherwise healthy cats, there's not much else. In terms of diagnostic investigations, cytology would probably be the first thing that you would do, so that would be looking for signs of secondary infection, which in the early stages of this problem there would be no evidence of infection because this is mediated problem.
The secondary infection would be possible and that would be important to identify. This condition is confirmed by biopsy. And if you were able to biopsy these cases, it would be important to try and collect crusts on the surface as well.
So this again is one of those sort of conditions where you don't really want to want to biopsy directly from an area of ulceration. You want to try and get that hyperplastic epidermis with crusty. And what the pathologist will see is a hypoplastic epidermis with scattered apoptotic or necrotic keratinocytes throughout the layers of the epidermis, which is which are those features that are similar.
To erythema multiforme. And we do often get quite striking parakeratotic hyperkeratosis, which is basically causing that. Scale, to form on the surface of the skin, which, would look like, scale crust, clinically.
Treatment options, tacrolimus cream 0.1% twice daily is mentioned in case reports of this condition and the advantage again of that for this particular condition is you're just treating the affected area without having to use a systemic medication for unaffected parts of the body. But there are also reports of cyclosporin being used for this condition, oral prednisolone.
And there's also a case report using intralesion and topical corticosteroid as well. The prognosis for this condition is generally good. Remember that some of them will spontaneously regress in time anyway.
But the time to resolution is variable, and with therapy that can be anywhere between 3 weeks and 12 months. So the conclusions are that necrotizing otitis externa. It is very distinctive, it causes symmetrical crusting and erosions in and around the ears of cats.
It often affects young cats and spontaneous remission is possible. Diagnosis is confirmed by biopsies. It's quite an awkward site to biopsy around the ears.
But that is, is really the only way of being definitive about the diagnosis. And topical tacrolimus is often effective, and that would probably be the treatment of choice in these cases. The next condition is juvenile cellulitis.
This also goes by the names of puppy strangles or juvenile sterile granulomatous dermatitis and lymphadenitis. This is an uncommon disorder of the face and pinning. Usually of young dogs, often puppies.
So I think of all the 5 conditions we've talked about today, this is probably the one that you're most likely to see in general practise, and probably many of you have already seen these cases. And this, this, this presentation often. Sort of associated with quite a worried owner because they've got a young dog that they've often not had for very long, and they've suddenly developed quite a severe skin disease.
And so it can also be quite an emotionally charged situation. The cause and pathogenesis of juvenile cellulitis are not known. Genetics are likely to be involved though because we know there are some breed predispositions including the golden retriever, Labrador, Gordon setter.
And action They're predisposed. This is likely to be an immune mediated. Because we have a good response to glucocorticoids.
And so far no infectious agents have been found. There have been some links to vaccines, possible vaccine reactions, because these dogs are often quite young and it's. Of developed not long after the time of initial puppy vaccinations, but nothing has been proven.
So in terms of clinical signs, this condition classically affects puppies and young dogs. Usually somewhere between about 3 weeks and 4 months old. But we do know that older dogs can be affected and there was a relatively recent case series of 90 adult dogs presenting with this type of pattern.
Dogs typically present with acute onset swelling of the face, involving the eyelids, the lips, and the muzzle. And we normally see quite striking submandibular lymph node enlargement as well. So when you feel these dogs, they've usually got sort of golf ball size lymph nodes underneath their jaws.
And because this is a mediated condition coming from within, symmetry is usually present. It is an acute onset condition though, so within 24 hours papules and pustules will usually develop again in these facially orientated areas, then draining tracts and crusting. The ear pin are usually affected, and secondary infectious otitis can develop.
And then in rare cases, areas like the prep use and perianal skin can become involved as well, but it's predominantly around the face and ears. This is just another picture of a dog that I saw some years ago. This was a very small little puppy.
And this is a dachshund, so this was a predisposed breed. This dog actually presented to the internal medicine service at the Royal Veterinary College with pyrexia and lethargy, and on examination, this dog had absolutely massive submandibular lymph nodes. You can see the periorbital swelling and edoema.
There's also some muzzle edoema in this little dog as well. Pruritus is not usually present, but lesions can be painful. Most of these dogs can be lethargic and depressed, as I mentioned, some can be pyrexic as well.
And in rare cases, they can also develop an immune mediated paniculitis, which is inflammation of the fat layer that the skin, and that's possible as well. You can see in this, Gordon setter we've got periorbital, swelling, edoema, and alopecia, and then multiple little papular lesions around the muzzle as well. So what are the differential diagnoses for this condition?
Well, in the very early stages when it's more just swelling, angioedema would be one of the possible, . Differentials angioedema is Basically on the spectrum of urticaria where the fluid is extending deeper within the skin, so it's a more more severe form of urticaria. In the later stages, bacterial infection would be on the list, but as I mentioned right back at the start, bacterial infection is actually quite rare on the face of the dog and wouldn't tend to have such an acute onset.
Demidiosis, well, these are young dogs with dermatitis affecting the face. So dermatocosis would need to be on the list, and, although it wouldn't tend to have such an acute onset, it would still be important to consider. Adverse drug reaction would need to be considered.
Some of these animals may have received routine flea and tick prevention, worming medication, that sort of thing. So it'd be important just to consider that as well. Cytology would probably be the number one diagnostic test to perform to start with, and that could be with an impression smear, for example, or if lesions have progressed to oozing, discharging lesions, you could attempt to gain obtain some of that fluid.
If there were intact pustules, you could try and, carefully open those pustules with a sterile needle and then collect some of the pustuar contents for cytology, for cytological psychological analysis as well. Now in juvenile cellulitis, the type of inflammation will be granulomatous. And you won't find microbes in the early stages of these in the early stages of this condition.
Obviously over time then there is a risk that you could get secondary bacterial infection on the top of it, but you won't find microbes at the start. Hair plucks and skin scrapes would be important to do just to help rule out demadiosis. And if you did perform a culture for bacteria bacteriology, that would be negative in the early stages.
Biopsies of the affected skin. Would show multifocal peri follicular granulomas and granulomas. So that's quite distinctive in that these granulomas tend to be sort of surrounding the hair follicles.
And if you performed tissue cultures on the tissue, that would, they would also be negative as well in this case. But do we need to do these diagnostic tests? Do we need to biopsy these dogs?
Well, this again would be one of those conditions where you may feel comfortable to make a clinical diagnosis. This presentation is quite distinctive. You've got a young dog, cute on set.
Facially orientated disease. Distinctive lesions and an early diagnosis is important, a little bit like the sinophilic bronchiosis of the face that we talked about at the start. An early diagnosis is important because these dogs can also have scarring.
If we leave these lesions to progress, then you could end up actually having quite a change of cosmetic appearance of the hair coat around the face if we don't treat them so. Yes, in many cases a clinical diagnosis is appropriate and you can start treatment without having to take biopsies and wait for 3 to 5 days to get the results back of that. So if you're happy that this is juvenile cellulitis and biopsies aren't going to be taken, remember also that many owners of young puppies don't necessarily want or aren't necessarily very keen for you to anaesthetize their puppy and take skin biopsies from around the face.
What they really want to do is just try and get a diagnosis and treatment underway as soon as possible, and I think in a case like this that would be justifiable given The features that there are and making that clinical diagnosis appropriate. So glucocorticoids are probably the treatment of choice here. We would tend to use prednisolone at 1 to 2 gigs per gig per day until clinical remission of lesions.
And that would usually take a couple of weeks. Again, it would be probably important, but it would be important to maintain that level of prednisolone until you, the clinician, have assessed that clinical remission and not just start to taper too soon because if you do start to taper that medication, that level of medication before clinical remission is obtained, you're just not going to obtain control of the condition properly. And you may need to use that dose for longer if there are signs of appendiculitis as well.
You may also need to consider treatment of secondary infection if that's been identified. And sometimes in rare cases you might need second agents such as cyclosporin, but in the majority of cases these dogs are going to respond very nicely to corticoids on their own. And then once clinical commission has been obtained, that can be tapered off relatively quickly.
The prognosis is usually very good. Relapses are uncommon even though we don't really know what actually is causing this type of reaction. Then most dogs don't have relapses in the future.
They can be weaned off their drugs and they go on to live completely normal lives, so the prognosis is normally good. So the conclusions for juvenile cellulitis are that this is a very striking disorder with an acute onset. It's usually seen in young puppies.
A rapid diagnosis is needed to prevent scarring of the skin. But biopsies are not always needed because of that distinctive clinical appearance and presentation. The condition usually responds very well to prednisolone over a few weeks, and the prognosis is usually good.
So thank you for listening to these 5 cases. We've discussed 5 dermatological disorders that are all relatively rare or uncommon, but they are all quite visually distinctive, so I hope going over them will be helpful for you in the future. Having knowledge of these conditions should help to make a quicker diagnosis, which is often important to have a better outcome.
Thank you for listening.