Les symptômes peuvent varier selon la cause, la zone touchée et la gravité. Reproduction is by budding on a broad base and from the same site at one pole (monopolar blastic development). Some cases present with paronychia with claw fold erythema and swelling, waxy or crusty brown exudate, red‐brown claw staining, or frenzied facial pruritus with varying, sometimes subtle, cheilitis or erythema of chin/ perioral skin. 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. Compared with KTZ + cefalexin. Oral antifungal drugs might be given by an intermittent/ pulsed dosing schedule to try to prevent recurrent Malassezia dermatitis (and otitis) in dogs and cats, particularly where topical therapy is either ineffective or impractical. Os comentários foram compartilhados eletronicamente com o GP e as respostas incorporadas no documento final. yeasts and extracellular cocci were recovered in higher numbers from the dorsal claw fold (following skin eversion) by gentle scraping with the sharp point of a tooth pick, when compared with tape‐stripping and direct impression using glass slides,296 likely reflecting enhanced cell exfoliation from the hard cuticle of the claw surface in this specialised site. Malassezia yeasts predominated on most of the sampled body sites and 11 Malassezia species (including M. pachydermatis) were directly identified by rRNA gene sequencing from the different clinical samples. By comparing the IgG response to M. pachydermatis antigens using western immunoblotting, a protein of 25 kDa was identified in the majority of atopic dogs with Malassezia dermatitis, but only a few atopic dogs without Malassezia overgrowth and none of the normal dogs, suggesting that this protein may have some clinical relevance in the pathogenesis of Malassezia hypersensitivity.207. A final possibility is that IgG responses to the yeast are merely an epiphenomenon and neither contribute to, nor inhibit, the ongoing disease process. The initial interplay between Malassezia organisms and the skin immune system is likely to take place in the epidermis.175 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 This indicates that Malassezia cell surface markers or metabolic products derived from the yeast may be able to directly damage the skin or induce pathogenic effects by activating the skin immune system.173 In order for this to happen, antigens or allergens produced or expressed by Malassezia spp. Table S1. Daniel O. Morris has received honoraria, consulting fees and/or has collaborated with Pfizer Animal Health/Zoetis, Bayer, and Ceva Animal Health. Table S4. From a zoonotic perspective, the pathogenic role best documented for M. pachydermatis is a syndrome of life‐threatening fungaemia that occurs in pre‐term neonates while receiving lipid‐rich nutritional infusions via catheter.469-475 Malassezia furfur is the primary skin‐colonizing species of human infants476 and is therefore the species most commonly implicated in this syndrome;477 however M. pachydermatis has also been clearly documented as an aetiological agent.469 For example, an epidemiological investigation of an outbreak occurring in a neonatal intensive care unit (NICU) identified a single strain of M. pachydermatis – as determined by pulsed‐field gel electrophoresis – which was isolated from 15 infants with sepsis, nine colonized infants, the hands of a nurse and three dogs owned by other health care workers in the NICU.469 In another study, 47 out of 86 M. pachydermatis isolates collected from 25 neonatal patients at a French University Hospital were genotyped using intergenic‐spacer 1 nucleotide sequence polymorphisms analysis.471 All 47 isolates clustered within sequence type 3 (most of them clustered within the 3D subtype, the remaining clustered within three newly described subtypes: 3E, 3F and 3G). Histopathological features in dogs often comprise hyperkeratosis or parakeratosis, irregular epidermal hyperplasia and spongiosis that extends to hair follicle infundibulae, lymphocyte and granulocyte exocytosis, and a mixed, predominately lymphocytic, superficial perivascular or interstitial infiltrate with variable superficial dermal oedema. E‐mail: firstname.lastname@example.org, Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, 3900 Delancy Street, Philadelphia, PA, 19104 USA, École nationale vétérinaire d'Alfort, BioPôle Alfort, EA 7380 Dynamyc, UPEC, EnvA, Maisons Alfort, Ile‐de‐France, France, Clinique Vétérinaire, 17 Boulevard des Filles du Calvaire, Paris, 75003 France, Animal Skin and Ear Specialists, Melbourne Veterinary Specialist Centre, 70 Blackburn Road, Glen Waverley, Victoria, 3150 Australia, Dermcare‐vet PTY LTD, 7 Centenary Road, Slacks Creek, Queensland, 4127 Australia, Department of Veterinary Pathobiology, Nihon University College of Bioresource Sciences, 1866 Kameino, Fujisawa, Kanagawa, 252‐0880 Japan, Department of Veterinary Science, University of Adelaide, Adelaide, South Australia, 5005 Australia. The original cutaneous microbiome studies mainly focused on prokaryotic inhabitants; thereafter fungi received more attention in humans and also in dogs and cats.117, 118 The first large‐scale sequencing analysis which evaluated fungal diversity (“mycobiome”) on human skin clearly demonstrated that Malassezia yeasts are the most abundant fungal organisms on many human skin sites, as previously shown for the scalp.119-121 In contrast to extensive bacterial diversity found at all human skin sites tested,122 the fungal diversity seems more site‐dependent.121 Eleven Malassezia species were identified with M. restricta being predominant in the external auditory canal, retroauricular crease and glabella; while M. globosa was on the back, occiput and inguinal crease. and systemic disease in the cat. Conventional and modern spectrum techniques were employed to characterise these isolates, encompassing morphology, ultrastructure, physiology and molecular biology. Pulsed therapy with itraconazole (5 mg/kg orally once daily, two days on/ five days off for three weeks) has been shown to be efficacious in the treatment of Malassezia dermatitis in dogs430 and thus should be effective as a preventative, although one report highlighted potential for development of antifungal drug resistance with pulse dosing (Section 11.5.2381). In one review,87 it was proposed that Malassezia yeasts are potential pathogens that operate in a pliable, physiological “transitional mantel zone” that is influenced by both host skin and the animal's external environment. Terbinafine was first shown to have activity in vitro against Malassezia spp. Malassezia dermatitis can potentially occur in dogs of any age, sex or breed, but signalment related predispositions have been reported. A concurrent bilateral erythematous otitis with black waxy exudate was reported in seven of 13 cats.395, Malassezia overgrowth has been found with cytology methods in approximately half of the reported cases, and more often with concurrent coccoid and/or rod bacterial overgrowth.395-397 In one study five of 12 cats partly responded to antimicrobial agents. Biofilms, wherein groups of adherent microbial cells become embedded in an extracellular polymeric matrix, may protect the microbe from the host immune system and reduce susceptibility to antimicrobial drugs.160 One study evaluated the in vitro antifungal susceptibility of M. pachydermatis strains, in both their planktonic and sessile (biofilm production) forms to fluconazole, posaconazole, voriconazole, miconazole, ketoconazole, itraconazole and terbinafine; MIC values were increased by 3–6 two fold dilutions in the sessile form.378 Another study reported an increase in itraconazole and ketoconazole MICs by nine two‐fold dilutions (<0.03 to >16 μg/mL) following biofilm formation in M. pachydermatis, either alone or when co‐cultured with Candida parapsilosis.383 A further study also reported that effective concentrations (EC50) of ketoconazole and itraconazole MICs increased by 18–169 and 13–124 times respectively against M. pachydermatis in biofilms when compared to planktonic forms.384 Another study reported reduced susceptibility of M. pachydermatis biofilms to azoles, terbinafine and amphotericin B.385 The significance of these important observations for therapy in clinical practice remains to be determined. Si votre chien présente un virus, le vétérinaire se chargera de vous conseiller le meilleur traitement. Analysis of the history of scientific discovery highlights the influence of language and geography, the role of experts and opinion leaders in study centres or in the modern day “centres of excellence”, and wider cultural effects that may impede or enhance investigation and implementation of technological advances in the pursuit of scientific progress. The isolation of M. globosa from the skin of a healthy cheetah (Acinonix jubatus) represented the first report of lipid‐dependent Malassezia spp from cats.20, 75 In 2004, a study described M. nana, a novel species from aural discharges of a cat and cattle.24 Some lipid‐dependent strains similar to the M. sympodialis type strain and isolated from cats were studied using DNA sequence analysis and grouped together with M. nana.110 Malassezia nana seems to be the most common lipid‐dependent species isolated from cats, particularly in the ear canal; similarities in the sequences of three loci of the rRNA gene,111 ß‐tubulin gene and microsatellite profiles112 indicate that a particular M. nana genotype predominates in this host. When paronychia is involved, there is reddish‐brown staining of the claws (Figure 5) or hair, with inflammation of the surrounding soft tissue. No: Sample more sites; use an alternative sampling method; reconsider diagnosis. Unfortunately trials assessing the in vivo efficacy of antifungal treatment for Malassezia dermatitis in dogs are few in number and commonly involve only small group sizes with resultant low statistical power. No statistical analyses, 5 mg/kg once daily for two consecutive days/week, Transient vomiting [n = 2], inappetence [n = 1], 6/13 dogs: transient vomiting [n = 4], vomiting and soft stool [n = 1], diarrhoea [n = 1]. Gustafson was able to induce a spontaneously‐resolving erythemato‐ceruminous otitis externa in healthy dogs by the application of a suspension of ‘P. 1996: The isolation of M. globosa from skin of a healthy cheetah (Acinonix jubatus) represented the first report of lipid‐dependent Malassezia spp from Felidae.20, 75 Bond et al.56 isolated the first lipid dependent species (Malassezia sympodialis) from domestic cat skin. Amplification of the chitin synthase 2 (CHS2) gene in seven Malassezia species yielded an ~620 bp fragment with 95% sequence homology between the species, although phylogenetic analyses indicated that each species was genetically distinct.34 Limited genetic variability in seen in the CHS2 gene amongst M. pachydermatis isolates from dogs in previous studies,315, 316 although wider variation was observed in another study.57 Partial sequencing of the ß‐tubulin gene in Malassezia provides a further opportunity for species and genotype differentiation.35, 112, 317, Genotypic approaches involving analyses of sequences obtained from multiple loci on the Malassezia genome, such as combined analyses of D1/D2, ITS, CHS2 and ß‐tubulin sequences, has proven to be a powerful tool in the epidemiological assessment of the intraspecific variations and adaptation of these particular genotypes to specific hosts.35, 57, 301, 318. This probably reflects exposure of the immune system to antigens produced by commensal organisms. pronounced irregular epidermal and infundibular hyperplasia; prominent epidermal and infundibular parakeratotic hyperkeratosis; diffuse epidermal and infundibular intercellular oedema (spongiosis); diffuse epidermal and infundibular lymphocytic exocytosis; superficial perivascular to interstitial dermatitis wherein lymphocytes are a prominent inflammatory cell type. In cats only open case series have been described, using oral itraconazole at varying doses and intervals (Table S7, LoE 3, SoR C‐weak).85, 86, 284 As for dogs, topical antifungal agents such as miconazole, chlorhexidine or climbazole are likely to be beneficial but there is no data to substantiate this, other than anecdotal reports. The role of this IgG response in the pathogenesis of skin disease is currently unclear, both in humans and dogs. Evidence for fluconazole is limited to a single study (LoE 2) where it was used at 5–10 mg/kg orally once daily in conjunction with cefalexin. and is regarded as a major pattern recognition receptor for both commensal and pathogenic fungi.169, 170 By contrast, Mincle, a C‐type lectin expressed by activated phagocytes that binds glucosyl and mannosyl‐glycolipids from M. pachydermatis and M. sympodialis,171 selectively recognises Malassezia spp. By counting yeast cells in a certain number of microscopical fields in the tape‐strip sample, a known area of skin surface is examined.266 Different brands of tape vary in their ability to resist staining procedures without crinkling or becoming opaque and a ‘trial‐and‐error’ approach is needed to identify suitable products from amongst those available locally. Traitement de l' otite externe du chien et du chat Dès lors, on comprend que plutôt que de changer maintes et maintes fois d'antibiotiques, et d’incriminer une éventuelle résistance bactérienne, il est préférable et nécessaire d'identifier à la fois un éventuel facteur prédisposant et surtout le ou les facteurs déclenchant à l'origine de l'otite. would need to penetrate the stratum corneum in order to be recognised by Langerhans cells or keratinocytes. Marked variations in populations between anatomical sites within the same dog are routinely described; for example, contact plates may yield confluent growth from the lip region of healthy dogs whereas counts are routinely much lower in the axilla and groin.257. Malassezia yeasts (chiefly M. pachydermatis) have been associated with a greasy seborrhoeic dermatitis in cats with or without concurrent paronychia.391 Predisposing diseases include poorly defined genetic factors (in Devon Rex and sphynx cats),80, 86, 115, 116 feline atopic dermatitis (which may present with concurrent bacterial pyoderma),85, 259, 284, 392 adverse food reaction,259, 284 flea bite hypersensitivity,284 although some recurrent cases are idiopathic despite diagnostic investigation.74, 284 There is conflicting evidence for diabetes mellitus as a predisposing cause.82, 284, 393 Feline immunodeficiency virus‐positive cats have been shown to carry more Malassezia organisms compared with normal cats but this was not associated with any clinical signs.394, Affected Devon Rex and sphynx cats typically show mild to marked greasy seborrhoea with alopecia (in Devon Rex) and hyperpigmentation or reddish‐brown surface discolouration and variable erythema affecting the axillae, groin, ventral neck and predominantly ventral interdigital regions.