Generalized dermatitis associated with Malassezia overgrowth in cats: A report of six cases in France (original) (raw)
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Retrospective study: the presence of Malassezia in feline skin biopsies. A clinicopathological study
Veterinary Dermatology, 2002
Malassezia spp. dermatitis, a rare disorder in cats, has previously been associated with immune suppression and internal malignancies. This study evaluates the presence and importance of Malassezia spp. in feline biopsy specimens submitted for histopathological examination. Five hundred and fifty haematoxylin and eosinstained skin biopsy specimens received for histopathological examination between January 1999 and November 2000 were reviewed. Fifteen (2.7%) submissions contained Malassezia organisms in the stratum corneum of the epidermis or follicular infundibulum. Eleven of 15 cats presented with an acute onset of multifocal to generalized skin lesions. All 11 cats were euthanized or died within 2 months of the onset of clinical signs. Seven cats had dermatopathological changes and clinical signs supportive of paraneoplastic alopecia, and three cats had an interface dermatitis suggestive of erythema multiforme or thymoma-associated dermatosis. Histopathological changes were nonspecific in one cat that was euthanized 2 weeks following onset of severe pruritus and alopecia. In three cats, Malassezia spp. were found in localized sites (two chin, one footpads) and appeared inconsequential to their overall health status. One cat had Malassezia spp. in association with cutaneous demodicosis. These findings suggest that Malassezia yeast in dermatopathological specimens from multifocal or generalized lesions should prompt a thorough clinical work-up for internal neoplasia.
Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats
Veterinary Dermatology, 2020
Background-The genus Malassezia is comprised of a group of lipophilic yeasts that have evolved as skin commensals and opportunistic cutaneous pathogens of a variety of mammals and birds. Objectives-The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention of skin diseases associated with Malassezia yeasts in dogs and cats. Methods and material-The authors served as a Guideline Panel (GP) and reviewed the literature available prior to October 2018. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) Clinical Consensus Guideline committee provided guidance and oversight for this process. The document was presented at two international meetings of veterinary dermatology societies and one international mycology workshop; it was made available for comment on the WAVD website for a period of six months. Comments were shared with the GP electronically and responses incorporated into the final document. Conclusions and clinical importance-There has been a remarkable expansion of knowledge on Malassezia yeasts and their role in animal disease, particularly since the early 1990's. Malassezia dermatitis in dogs and cats has evolved from a disease of obscurity and controversy on its existence, to now being a routine diagnosis in general veterinary practice. Clinical signs are well recognised and diagnostic approaches are well developed. A range of topical and systemic therapies is known to be effective, especially when predisposing factors are identified and corrected.
Journal of Feline Medicine and Surgery, 2013
In contrast to single-celled yeasts, dermatophytes ('skin plants') are complex fungi growing as hyphae and forming a mycelium. About 40 species belonging to the genera Microsporum, Trichophyton and Epidermophyton are considered as dermatophytes. Over 90% of feline dermatophytosis cases worldwide are caused by Microsporum canis. 1 Others are caused by M gypseum, T mentagrophytes, T quinckeanum, T verrucosum or other agents. With the exception of M gypseum, all of these agents produce proteolytic and keratolytic enzymes that enable them to utilise keratin as the sole source of nutrition after colonisation of the dead, keratinised portion of epidermal tissue (mostly stratum corneum and hairs, sometimes nails). Dermatophytes produce arthro spores, which are highly resistant, surviving in a dry environment for 12 months or more [EBM grade III]. 2 In a humid environment, however, arthro spores are short-lived. High temperatures (100°C) destroy them quickly. Arthrospores adhere very strongly to keratin. Depending on the source of infection and reservoirs, dermatophyte species are classified into zoophilic, sylvatic, geophilic and anthropophilic fungi. Epidemiology Dermatophytosis is worldwide the most common fungal infection of cats and one of the most important infectious skin diseases in this species. It may be transmitted to other animal species, and is also an important zoonosis. M canis is a typical zoophilic dermatophyte. It was generally thought that subclinical infections are very common in cats, especially in longhaired animals over 2 years of age. However, in many groups the prevalence is relatively low. Therefore, M canis
Veterinary Dermatology, 2020
Background-The genus Malassezia is comprised of a group of lipophilic yeasts that have evolved as skin commensals and opportunistic cutaneous pathogens of a variety of mammals and birds. Objectives-The objective of this document is to provide the veterinary community and other interested parties with current information on the ecology, pathophysiology, diagnosis, treatment and prevention of skin diseases associated with Malassezia yeasts in dogs and cats. Methods-The authors served as a Guideline Panel (GP) and reviewed the literature available prior to October 2018. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) Clinical Consensus Guideline committee provided guidance and oversight for this process. The document was presented at two international meetings of veterinary dermatology societies and one international mycology workshop; it was made available for comment on the WAVD website for a period of six months. Comments were shared with the GP electronically and responses incorporated into the final document. Conclusions and clinical importance-There has been a remarkable expansion of knowledge on Malassezia yeasts and their role in animal disease, particularly since the early 1990's. Malassezia dermatitis in dogs and cats has evolved from a disease of obscurity and controversy on its existence, to now being a routine diagnosis in general veterinary practice. Clinical signs are well-recognised and diagnostic approaches are well-developed. A range of topical and systemic therapies is known to be effective, especially when predisposing factors are identified and corrected. 1853 Charles Robin named Eichstedt's fungus as Microsporon furfur, believing it to be a dermatophyte, and termed the associated skin disease "Tinea versicolor". 39 1873 Sebastiano Rivolta, an Italian veterinarian, noticed a double-contour budding yeast in human "psoriatic" scales and gave them the name Cryptococcus psoriasis. 40 1874 Frenchman Louis Charles Malassez 41 suggested that Microsporon furfur caused dandruff and correctly differentiated the yeast into genus of single cell fungi ("Saccharomyces") rather than the dermatophyte complex. For this correction, his name was ultimately attached to the genus. 42 3.2.2. Attempts at classification without laboratory isolation 1884 Bizzozero studied these microbes and described them to be part of normal human skin flora. He claimed there were two different species and named them Saccharomyces ovalis and S. sphaericus. 43 However, these were later shown to be a single species. 44 1889 Baillon created the genus Malassezia to accommodate M. furfur, in honour of Malassez, who was already acknowledged as having described the new species-at least in the French-speaking scientific community. 17 However this particular yeast could not be grown and isolated in laboratory conditions because its lipid requirement in culture media were as yet unknown. 1910 Raymond Sabouraud, a prominent medical mycologist, proposed the name Pityrosporum malassezi for this bottle shaped yeast thought to cause human dandruff. 45 1913 Alfred Kraus was able to culture P. malassezi in a medium containing lanolin. 46 In a prime example of the effect of geography and historical events on scientific discovery, this German scientist's work was largely overlooked with the onset of the First World War. 3.2.3. Diseases associated with Malassezia 3.2.4. The controversy and 'Dark Years': 1940 to 1960 1940-1960 are known as the 'Dark Years' and spanned a period of more controversy. The hard won progress in the field was forgotten as a consequence of the Second World War and the overwhelming effect of cortisone treatment becoming available in the late 1940s, to which human seborrhoeic dermatitis responded. The role of Malassezia yeasts in the disease was thus forgotten. 1970 The systematics were rectified when Sloff in Lodder's 'The Yeasts, a taxonomic study' assigned all Pityrosporum that grew on media without lipid enrichment as single species of P. pachydermatis. 52, 53 1984 The third edition of 'The Yeasts, a Taxonomic Study' (Yarrow and Ahearn) referred to the new genus Malassezia and confirmed that one species grew without lipid enrichment. 54 This was later officially added into the taxonomical order. 55 1990 A new species, Malassezia sympodialis was described 19 and by 1996 four new species were added to the genus. 20 This species was later isolated from a cat by Bond et al. in 1996. 56 3.2.5 Modern approaches Currently there are 18 different species of Malassezia. 35,57 The genus continues to expand and this is likely to continue as the classical 'bottom-up' microbiological approaches merge with organism-level genomics and community or 'systems-level meta-genomics'.
Evaluation of dermoscopy in the diagnosis of naturally occurring dermatophytosis in cats
Veterinary Dermatology, 2016
Background-A rapid, accurate screening test for dermatophytosis in cats is desirable in clinical and shelter medicine. In human dermatology, dermoscopy is used to identify dermatophyte-infected hairs by their characteristic comma hair appearance. Similar "comma-like" hairs have been observed in infected cats. Hypothesis/Objectives-The purpose of this study was to evaluate the usefulness of dermoscopy for the diagnosis of naturally occurring dermatophytosis compared to fungal culture. Animals-A total of 67 cats were enrolled. Methods-This was a descriptive field study. All cats were evaluated by dermoscopy and fungal culture. Dermoscopy was performed with a hand held nonpolarized light dermoscope. Results-Three dermatophyte pathogens were isolated via fungal cultures in 36 cats: Microsporum canis (n = 31), Microsporum gypseum (n = 3) and Trichophyton mentagrophytes (n = 2). Dermoscopy was positive in 21 of 36 cats with culture-confirmed dermatophytosis. Conclusions and clinical importance-Dermoscopy may be a useful point-of care-test to identify infected hairs to sample for dermatophyte cultures, but a definitive diagnosis for dermatophytosis should be based on clinical signs and the results of multiple diagnostic tests.