Read and chat Malassezia

RE: Read and chat Malassezia

Anthony Todd — Wed, 15 Apr 2020 12:14:15 GMT

[quote userid="12930" url="~/001/veterinary-clinical/small-animal/dermatology/f/discussions/29005/read-and-chat-malassezia/221753"]There is one more bit I missed out, Anthony T, if of minor interest. Similar situation regarding skin not in ear canal that I hadn't noted earlier:[/quote]

Fair doos, can't argue out of that, and beagles aren't too "allergic"either. [c/f westies!]

I don't think i can remember seeing dogs with that sort of reaction that didn't respond best to just C'steroids though?? But, to be fair, they were all very "allergic"

I wonder why ears canals are different, ie don't become "infected" with Mal?

We had a spaniel with probably exactly the lesions you describe, and all sorts of other skin problems, which became incandescent when we cleaned the "oily skin" with ether then began to cauterise a wart with a red-hot cautery tip......

RE: Read and chat Malassezia

Beats — Wed, 15 Apr 2020 11:46:10 GMT

[quote userid="5904" url="~/001/veterinary-clinical/small-animal/dermatology/f/discussions/29005/read-and-chat-malassezia/221443"]Gustafson was able to induce a spontaneously-resolving erythemato-ceruminous otitis externa in healthy dogs by the application of a suspension of ‘P. canis’ to the external ear canal.58[/quote]

There is one more bit I missed out, Anthony T, if of minor interest. Similar situation regarding skin not in ear canal that I hadn't noted earlier:

"The effects of the daily application for 7 days of suspensions of Malassezia pachydermatis to normal canine skin were evaluated in 10 beagle dogs. Four out of six dogs challenged without occlusion developed transient lesions generally characterized clinically by mild erythema with papules and histologically by mild epidermal hyperplasia and a superficial perivascular dermatitis. Saline-treated control sites showed no clinical signs." 176. Bond R, Patterson-Kane JC, Lloyd DH. Clinical, histopathological and immunological effects of exposure of canine skin to Malassezia pachydermatis. Med Mycol 2004; 42: 165–175.

[quoted (in passing) on p. 12 of initial reading as: "It has been demonstrated that application of M. pachydermatis suspensions on healthy dog skin can induce skin lesions similar to those observed in naturally occurring Malassezia dermatitis.176"; for context, this section is discussing about the local immune response interactions between Malassezia and keratinocytes.]

RE: Read and chat Malassezia

Anthony Todd — Sat, 04 Apr 2020 11:42:42 GMT

[quote userid="12930" url="~/001/veterinary-clinical/small-animal/dermatology/f/discussions/29005/read-and-chat-malassezia/221434"]I have no desire to chasten you, Anthony T, but you might find p.8 an interesting read when you get there (bold emphasis) section I was thinking of, I have copied below in context:[/quote]

Thanks for the quotes, and I suspect I'll be accused of flogging a dead horse, but all your evidence shows [IMHO] is that with otitis externa you often get an increase in yeasts, no doubt or dispute at all, simple cause and effect.

Except I say the egg comes before the chicken?

My contention is still that this increase in Pcanis is in response to the increased sebum production because of the otitis and not the reverse. The otitis, starting as the allergic response comes first and the increased sebum fuels the increased numbers of P.canis.

Gustafson was able to induce a spontaneously-resolving erythemato-ceruminous otitis externa in healthy dogs by the application of a suspension of ‘P. canis’ to the external ear canal.58 1961 surely supports this.

On the one hand P canis "causes the condition" yet when you "infect"an ear it doesn't, just dies away which, I suggest, is because there ain't enough sebum which is exactly and totally my point.

Which is why the dreaded C'roids which diminish the sebum production work as the P.canis dies of starvation!

And the patient, by the way, and I know this is not really the point, gets relief within, what, 2 hours??!!

RE: Read and chat Malassezia

Beats — Sat, 04 Apr 2020 07:27:35 GMT

[quote userid="5904" url="~/001/veterinary-clinical/small-animal/dermatology/f/discussions/29005/read-and-chat-malassezia/221427"]I'd be chastened and give in, if you could produce an otitis, which you say is possible, in a normal un-allergic dog's normal canal just by instilling Mal. in that dog's external canal.[/quote]

I have no desire to chasten you, Anthony T, but you might find p.8 an interesting read when you get there (bold emphasis) section I was thinking of, I have copied below in context:

3.3.2 Malassezia yeasts in the canine and feline ear 1955: Gustafson was the ﬁrst to notice a bottle shaped yeast in otitis externa of a dog; he correctly recognized them as Pityrosporum and created a new species P. canis.58 This was in error as he had misread Lodder’s description and failed to consider Weidman’s discovery of the yeast in rhinoceros skin, which grew without lipid enrichment. Gustafson was able to induce a spontaneously-resolving erythemato-ceruminous otitis externa in healthy dogs by the application of a suspension of ‘P. canis’ to the external ear canal.58 1961: Fraser also isolated and studied strains of yeast from healthy and diseased dog ears and correctly ascribed all as P. pachydermatis. During the next two decades, a number of studies showed the connection between canine otitis externa and P. pachydermatis.59,60 1976: Baxter also showed that, unlike previously thought, the frequency of isolation of P. pachydermatis was comparable in healthy ears and in cases of otitis externa in dogs’ and cats’ ears.61

58 = Gustafson BA. Otitis externa in the dog. A bacteriological and experimental study. Stockholm: Gernandts Boktryckeri (Royal Veterinary College thesis). 1955; 117 pp. [and no, I haven't read that 117pages to follow-up on the methodology yet...! Valid questions might be "what else was in the suspension?" for instance]

59 = Sinha BK, Mohapatra LN, Kumar R. Studies on otitis externa in dogs. 1. Survey of aetiological agents: fungi. Mykosen 1976; 19: 63–69.

60 = Baxter M, Lawler DC. The incidence and microbiology of otitis externa of dogs and cats in New Zealand. N Z Vet J1972; 20: 29–32.

61 = Baxter M. The association of Pityrosporum pachydermatis with the normal external ear canal of dogs and cats. J Small Anim Pract 1976; 17: 231–234.

RE: Read and chat Malassezia

Anthony Todd — Fri, 03 Apr 2020 21:35:40 GMT

Fair enough, I have no answers, but you'd really need to look at the histories and any previous anything..May well be that some "sebum" is better than others;

Loads of possibilities.

But then you seem to agree with me???

Have you any answers? What is your point or points??

I'd be chastened and give in, if you could produce an otitis, which you say is possible, in a normal un-allergic dog's normal canal just by instilling Mal. in that dog's external canal.

Must be easy to test?

PS Whatever, wherever and how ever Csteroids, in an "irritated" ear canal, [without an obvious injury or otitis] will improve with Csteroids, which is often forgotten in the drive to "cure", as oppose relieve, that irritation.

The reduction of the Mal. population is, IMHO, purely incidental.

I suppose I'll be happy, not by possibly winning an argument, but rather if I can get a decent topical C'steroid added to the treatment regime and if it becomes accepted.

It always helped, even cured, a lot in mine and I never treated Mal. ever.

In the 80s over 7% of all consults were ears which was a lot....

RE: Read and chat Malassezia

Beats — Fri, 03 Apr 2020 19:20:24 GMT

[quote userid="5904" url="~/001/veterinary-clinical/small-animal/dermatology/f/discussions/29005/read-and-chat-malassezia/221406"]Just tell me why a "probable", and I've got no evidence, massive increase in sebum [or what the name now is] via the allergic response wouldn't lead to a massive increase in malazzesia numbers and give rise to an illogical diagnosis??[/quote]

Not all dogs with allergic skin disease, including some very badly affected Westies, get overgrowths in Malassezia on cytological tape strips.

Some do, some don't.

Why do some and not others?

What would happen to the ones that don't have large amounts of Malassezia on them if you then put Malassezia from another dog on them? Would it matter if it was from a dog with healthy skin or a dog with extensive Malassezia overgrowth and dermatitis?

RE: Read and chat Malassezia

Beats — Fri, 03 Apr 2020 19:14:39 GMT

Loving the chat, Anthonys.

I haven't finished reading it all yet myself, but you seem to have hit on an argument that has raged through the centuries (well at least in the 1990's w.r.t. Malassezia in English-speaking vet derm circles).

I think the truth may be perhaps more nuanced though than it being characterised as a dichotomy of innocent-spectator or sole-conspirator.

Malassezia innoculated can cause lesions I believe, but in a patient that does not suffer from dermatitis these are likely to self-resolve.
Not all Malassezia are created equal, some strains are, perhaps, more pathogenic than others.
Some atopic dogs appear to be allergic to malassezia; anti-yeast treatment may not cure them of atopy, but it can control their signs by removing a significant allergen.
Equally, treating the allergic reaction to the malassezia can resolve the signs.
In atopic dogs, the defective skin barrier plays a large role it is thought, Malassezia may both be opportunist pathogens (much like Staphylococci) or, perhaps more sinsterly, may contribute to the defective skin barrier through it's effects on the lipid barrier etc.
Increased amounts of Malassezia present may be both a consequence of allergic dermatitis AND a contributing factor to that dermatitis.

I went off on a tangent and read up on Pityriasis versicolor in people having been intrigued by the historical discussion near the start - fascinating stuff!

RE: Read and chat Malassezia

Anthony Todd — Fri, 03 Apr 2020 18:26:34 GMT

You cry out for responses to your queries or statements to be supported by evidence based medicine, but you're using anecdotal/eminence [er, evidence??] based to support your version of events?

All I want is some evidence to refute my experience. AllI I express is my experience, which I haven't imagined..

[quote userid="11308" url="~/001/veterinary-clinical/small-animal/dermatology/f/discussions/29005/read-and-chat-malassezia/221404"]You cry out for responses to your queries or statements to be supported by evidence based medicine, but you're using anecdotal/eminence based to support your version of events?[/quote]

"eminence", er, well, not on here I wager..joking

Malassezia is taking the opportunity, because of the increased sebum production, therefore numbers obviously multiply!

The lab.techs find the culprit and there you go....

If it was a commensal it wouldn't die out, it would just reduce numbers. You've contradicted yourself now.

Oh dear, it's sitting there, the "food supplies" multiply by !000%x in response to the allergic insult, and increased sebum and you say the commensal numbers reduce??!!!

I'm getting fatter 'cos I eat more, not less......!!.

Just tell me why a "probable", and I've got no evidence, massive increase in sebum [or what the name now is] via the allergic response wouldn't lead to a massive increase in malazzesia numbers and give rise to an illogical diagnosis??

RE: Read and chat Malassezia

Anthony Dennison — Fri, 03 Apr 2020 16:37:19 GMT

[quote userid="5904" url="~/001/veterinary-clinical/small-animal/dermatology/f/discussions/29005/read-and-chat-malassezia/221398"]I can only write of my experiences where the fungus apparently died out when the discharge/exudate/sebum was reduced by minimising the cause, ie reducing the causative allergic reaction.[/quote]

You cry out for responses to your queries or statements to be supported by evidence based medicine, but you're using anecdotal/eminence based to support your version of events?

The animal is having an allergic reaction to something. Malassezia is taking the opportunity and numbers multiply. If it was a commensal it wouldn't die out, it would just reduce numbers. You've contradicted yourself now.

Yes there are cases where treat the underlying inflammation and the Malassezia go away. There are also lots of cases where that doesn't happen and specific antifungal treatment is required. It would be nice of you to realise/accept this rather than say 'well I treated with steroids and it went away, which means I must be right'.

[quote userid="5904" url="~/001/veterinary-clinical/small-animal/dermatology/f/discussions/29005/read-and-chat-malassezia/221398"]This is where I beg to differ! Just as easily, and my argument is, that the "atopy/allergic response" is the cause of the high numbers, via increased exudate giving a greater source of "nutrients"and not the reverse...[/quote]

What is the allergic response to? Given the fact that allergy testing includes Malassezia it could well be the causal factor. Trying to determine the 'flare factor' that is the causal agent, be it dietary intolerance, allergy to something like pollen, house mites, dust mites etc. is now the mainstay in skin work ups. Even the product inserts for apoquel and cytopoint say that skin work ups should be started before long term use of their medications.

RE: Read and chat Malassezia

Anthony Todd — Fri, 03 Apr 2020 14:45:09 GMT

I can only write of my experiences where the fungus apparently died out when the discharge/exudate/sebum was reduced by minimising the cause, ie reducing the causative allergic reaction.

Yes malassezia can be found on normal skin in low numbers, but in high numbers it can exacerbate the atopy/allergic response and become a problem in it's own right rather than just a consequence of sore skin.

This is where I beg to differ! Just as easily, and my argument is, that the "atopy/allergic response" is the cause of the high numbers, via increased exudate giving a greater source of "nutrients"and not the reverse...

PS 16.5 "conclusions" refers ro "hydrocortisone cream" as a trial treatment in 2020!!...... which even the most steroidophilic probably wouldn't call the most effective prep.today [shades of the 1950s?] One wonders how triamcinolone would have fared?

Neither, as far as I can see, does anyone just try only a potent steroid topical or parenteral which, I suggest might change thinking.

RE: Read and chat Malassezia

Anthony Dennison — Fri, 03 Apr 2020 13:58:27 GMT

Have you read the paper Tony?

I think grouping every Malassezia case together as a single disease entity that should be treated the same way (suprise surprise, steroids) is not beneficial to individual animals. I have seen some cases where the atopy and skin irritation is controlled, but there is still a yeast overgrowth that has required oral antifungals.

Just because something is a commensal doesn't mean it won't become pathogenic if the conditions are right and the opportunity arises. MRSA has been found as a commensal... look at the damage that can do. Yes Malassezia can be found on normal skin in low numbers, but in high numbers it can exacerbate the atopy/allergic response and become a problem in it's own right rather than just a consequence of sore skin.

RE: Read and chat Malassezia

Anthony Todd — Fri, 03 Apr 2020 12:14:44 GMT

I know there will be howls of derision but, over the years I, and I'm sure all other dinovets, have seen loads of these dogs, particularly, and classically, WHW terriers.

It must have been the commonest reason for a WHW to present!!

The picture is classical as shown , although the distribution is often more rear end.

They always responded rapidly to corticosteroids alone, topical or systemic and pretty well any ancillary topical prep. and, as far as I recall, results were always good although, as we all assumed it was an allergic response, it always returned, often seasonally, as expected.

. Control, and management was usually able to be commenced next time way before the patient got anywhere near the one in the post and results and the very important relief quick and total.

I think Malassezia is a commensal, always present in most/all dog's ears, and with an allergic reaction in the ear canal the sebum increases massively and so does the number of Malassezia.......

My only evidence is that the dogs always got better, and quickly too, without any, additional,or specific treatment of the Malassezia and the condition usually recurred, often seasonally.

When the sebum/"wax" production returned to normal the canal returned to the usual slightly oily appearance until the next allergic insult

Surely this does not happen with an infectious or pathogenic condition??

RE: Read and chat Malassezia

Dinu Catilina — Fri, 03 Apr 2020 10:30:59 GMT

Sorry Beats, I donwloaded, opened it and decided I'll wait for someone else's review. That's a lot of pages ...

RE: Read and chat Malassezia

Jo Dyer — Fri, 03 Apr 2020 09:17:05 GMT

Oh gosh, 49 pages, that could take a while! I do love a bit of dermatology though