Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

Abstract

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.

Antifungal Resistance Regarding Malassezia pachydermatis: Where Are We Now?

“…The overgrowth of yeast is encouraged in presence of a cutaneous microenvironment modified by a primary inflammatory process, particularly in the course of diseases that cause increased moisture, increased sebum production, altered surface lipids, the disruption of the stratum corneum barrier function, or aberrant immune responses [4].…”

“…Current options for the treatment of MD and MO include, in addition to various antiseptics such as selenium sulphide and chlorhexidine, systemic and topical therapy with several antifungal agents [4,[9][10][11][12][13][14][15][16][17][18]32]. The most commonly used antifungals for dogs belong to various chemical classes with different mechanisms of action (Table 1).…”

“…pachydermatis is a commensal organism commonly found on the skin, in ear canals, and on the mucosal surfaces of healthy dogs. Favourable growth conditions in the local environment allow the excessive multiplication of this organism, which may then function as an opportunistic secondary pathogen [4][5][6]. Dogs may present with Malassezia otitis (MO), dermatitis (MD) (either localised or generalised), or both [6].…”

“…Though M. pachydermatis predominates in dogs, other species, such as M. furfur, have been occasionally reported in cases of dermatitis or otitis [4].…”

Malassezia spp. Yeasts of Emerging Concern in Fungemia

“…For treatment of Malassezia- related infections, azoles, and the polyene AmB are frequently employed, both in humans and animals. Topical antifungal agents (mainly azoles) are adequate for the management of localized skin lesions, while systemic ITZ or FLZ for severe skin diseases (Bond et al, 2020 ; Saunte et al, 2020 ). For catheter-related Malassezia infections, there are only recommendations, and patients were usually treated with catheter removal, discontinuation of lipid infusion and administration of antifungal drugs such as FLZ, AmB, and or VOR (Arendrup et al, 2014 ; Table 1 ).…”