Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats (original) (raw)
Related papers
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'.
Occurrence of Malassezia species in healthy and dermatologically diseased dogs
Mycopathologia, 2004
The presence of Malassezia spp. yeasts was investigated in dermatological specimens of 224 dogs, 164 dermatologically diseased and 60 normal dogs. Subjects included in the study were of different breed, age, sex and habitat. Malassezia spp. positive cultures were obtained in 142 (63.4%) specimens: 67.6% from dermatologically diseased subjects and 51.6% from healthy dogs. Malassezia pachydermatis, either as a pure
2019
Yeasts of the genus Malassezia are commonly isolated from different areas of the body in dogs diagnosed with atopic dermatitis. The proliferation of these yeasts may trigger clinically relevant hypersensitivity responses in patients with CAD. There are also reports that there is some association with certain body areas and predisposing factors such as gender, race, or age, among others. The objective is evaluate the factors associated with the presence of Malassezia spp. yeasts in dogs with atopic dermatitis in Quito, Ecuador. A total of 800 patients who attended a dermatological clinic at Veterinary Care Centers in Quito were evaluated, among whom 10% (80 dogs) were diagnosed with CAD. Epidemiological data were collected and cytological samples comprising ear culture swabs, imprints, or Scotch tape samples from different areas of the body, were taken. Each sample was stained and analyzed under the microscope. The 86.2% of dogs with CAD presented Malassezia spp. Dogs aged less than ...
Malassezia Species Associated With Dermatitis in Dogs and Their Antifungal Susceptibility
International Journal of Current Microbiology and Applied Sciences
The present study was taken with the objective of isolation, characterization, molecular detection and antifungal sensitivity of Malassezia species from dermatitis cases from dogs in and around Pondicherry state. A total of 100 skin swabs were collected from the dogs showing dermatological problems suggestive of Malassezia. Out of 100 swabs, 41 Malassezia isolates were successfully isolated and had good growth on Sabouraud's Dextrose Agar (SDA) during the primary isolation from the skin swabs. Biochemical tests for catalase, β-glucosidase activities and the capability to grow with three water soluble lipid supplements, namely Tween 20, Tween 80 and Cremophor EL concluded that the M. pachydermatis was the sole species isolated from the cases of canine dermatitis in Pondicherry state. Cytological examination revealed that direct skin swab smear was more sensitive than adhesive tape technique and impression smear. The frequency of isolation of M. pachydermatis was higher in neck region (8) followed by other regions in canine. Out of 100 skin swabs screened using an M. pachydermatis species specific primers, 61 were identified positive. The study showed a higher sensitivity of PCR (61%) in detecting Malassezia dermatitis over culture (41%). Based on invitro antifungal susceptibility studies it can be concluded that Ketoconazole, Itraconazole, Fluconazole and Amphotericin B can be advocated as the drug of choice to treat Malassezia dermatitis in this geographical location.
Journal of Veterinary Diagnostic Investigation, 2005
Malassezia species are commensal organisms of human and animal skin that occasionally act as opportunistic pathogens. The lipid-dependent species are associated with human skin disorders, whereas the non-lipid-dependent species (Malassezia pachydermatis) is considered as an opportunistic secondary pathogen affecting the canine skin surface and ear canal. This study evaluated the relationship between Malassezia yeasts, their population size, and the occurrence of skin lesions from healthy and skin-diseased dogs. The efficiency of cytological examination and fungal culture for Malassezia detection was also evaluated. From March 2002 to July 2003, 33 healthy dogs and 54 dogs with pruritic localized skin diseases were examined; skin swabs (1218) were collected from 7 anatomical sites for culture and cytological examination. Malassezia prevalence according to anatomical site and the agreement between cytological results and fungal cultures were statistically analyzed. Differences in mean colony forming unit counts between positive healthy and diseased dogs were evaluated using the Bonferroni test for post hoc pair-wise comparisons. In healthy dogs, Malassezia yeasts were most frequently isolated in the perianal and perioral areas. The frequency of isolation and population size of Malassezia species were higher in dogs with localized dermatitis, especially in affected areas, indicating a role for Malassezia in the occurrence of skin lesions. Malassezia pachydermatis was the species most commonly cultured from the skin and external ear canal of healthy and diseased dogs; isolation of lipid-dependent yeasts from healthy dogs was less frequent. Using fungal culture as the gold standard, cytological examination showed good relative specificity (95%) but very low relative sensitivity (30%).
Medical Mycology Case Reports, 2013
We recently observed six cases of generalized dermatitis associated with Malassezia overgrowth in cats presented to the Veterinary College of Alfort, France. Elevated numbers of yeasts were observed in lesional skin by cytology and culture. Skin lesions occurred on the face, ventral neck, abdomen and ear canals and were characterized by some degree of alopecia, erythema and crusting. In most cases, pruritus was intense. The species M. pachydermatis was systematically isolated.
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.
Turkish Journal of Veterinary and Animal Sciences, 2011
Malassezia yeasts are commensal organisms on the skin of warm-blooded vertebrates. Th e lipid-dependent Malassezia species have recently been cultured from veterinary specimens. Th e present study investigated and compared diff erent Malassezia species in the skin and external ear canal of healthy and diseased dogs. Th e sampling in the study was carried out on 152 animals, comprising 90 samples from the diseased group and 62 samples from the healthy group. All of the samples were determined by cytological examination and fungal culture. Th e isolated yeasts were identifi ed by their morphological features as well as their physiological characteristics. Th e culture results were positive in only 32.2% samples, including 75.5% samples from the diseased group, and 24.5% samples from the healthy group. A total of 75 strains from 6 Malassezia species isolated from both groups were detected with a frequency rate as follows: M. pachydermatis (56%), M. sympodialis (28%), M. furfur (8%), M. obtusa (5.4%), M. globosa (1.3%), and M. restricta (1.3%).
Diagnostic and clinical features of animal malasseziosis
Parassitologia, 2008
Malassezia yeasts infection represents a common clinical concern with a special regard to canine dermatology. The Authors review the main clinical features of malasseziosis in canine and feline medicine, summarizing predisposing factors and aetiopathogenesis of the yeasts' infection. A special reference was given to clinical and microscopical diagnosis.