An update on Malassezia infections in animals – clinical signs and diagnostic approach

Autor: Hađina, Suzana, Stevanović, Vladimir, Barbić, Ljubo, Martinković, Krešimir, Milas, Zoran, Turk, Nenad, Starešina, Vilim, Štritof, Zrinka, Habuš, Josipa, Perharić, Matko, Pinter, Ljiljana
Přispěvatelé: Antolović, Roberto
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Popis: Malassezia yeast is an opportunistic yeast regularly present on the healthy and diseased animal skin. Until today there are fourteen identified and thoroughly described species in total. M. pachydermatis is the most commonly isolated species, causing pathological changes on the skin not only in dogs and cats, but also in domestic animals. Its distribution is determined by the amount of lipids on the animal skin. Concentration of Malassezia yeast on dog’s affected area can be up to thousand folds higher in comparison with the number of Malassezia colonies that inhabit healthy parts of the skin. Pathogenesis of Malasssezia infections is still not completely elucidated. Its occurrence is connected to yeasts' virulence factors, host immune response and skin microenvironment. Otitis and dermatitis of different body regions are most commonly seen clinical conditions in dogs, less often in cats and sporadically in farm and wild animals. Animals that suffer from Malassezia otitis usually have erythematous and swollen pinna, scaling of inflamed external ear canal containing brownish cerumen discharge and specific malodor. Dermatitis is usually characterized with erythema and alopecia of inflamed skin area. Abdominal region, body skin folds and limbs are typically affected. If not treated, in chronic cases skin becomes greasy, thickened, hyperpigmented and lichenificated. Malassezia dermatitis is not easily diagnosed by the clinical signs alone because it usually occurs as the complication of atopic dermatitis, consequence of food sensitivity reactions or with various concurrent diseases. Clinical diagnosis is usually based on the examination of direct smear impression of swabs or scotch tape and their cytological evaluation. Culturing technique is the most accurate identification of Malassezia yeasts based on their microscopic morphology and phenotypic characteristics. Difficulties in culturing this yeast, especially lipid dependent strains, very often lead to making diagnosis based only on the response to antifungal therapy or in complicated cases on histopathological findings. Recently MALDI-TOF has been proposed as the new rapid laboratory diagnostic tool in Malassezia skin diseases in order to improve the time and accuracy of identification. However, its use in routine diagnostic of Malassezia infections is still limited.
Databáze: OpenAIRE