Modern concepts of Malasseziosis in dogs

The genus Malassezia includes twelve species of yeast, many of which have been mainly associated with human and canine diseases. Malassezia pachydermatis colonizes the skin and mucosal sites of healthy dogs and cats. Despite being part of the normal cutaneous microflora, Malassezia spp. yeast may become pathogenic under certain circumstances. Malassezia yeast infection represents a common clinical concern with a special regard to canine dermatology. The author reviews the main clinical features of malasseziosis in canine medicine, summarizing predisposing factors and aetiopathogenesis of the yeast's infection with an aim to review and discuss the scientific literature available on the pathogenesis of Malassezia spp. A special reference has been given to clinical and laboratory diagnosis. Most cases of Malassezia dermatitis/otitis in the dog are associated with concurrent dermatoses or systemic diseases and recurrences are not uncommon. Recognition and control of the predisposing factors are therefore, key factors for successful therapy and prevention of recurrent infections. Currently, Malassezia dermatitis/otitis is managed by the use of antifungal drugs. Systemic therapy is often necessary, in particular when clinical signs are severe and widespread. Ketoconazole and Itraconazole are the most commonly used drugs. Topical therapy is an alternative in case of localized lesions and external ear localizations. Different commercial formulations, available in clinical practice in form of creams, gels, lotions, sprays and ear drops are often used as adjuvants to systemic therapy. Topicals more frequently used are represented by imidazolic antifungals, chlorhexydine and lime sulphur. The presentation deals with more recent advances about the protocols for treatment of Malassezia-related diseases in the dog. New perspectives, as the use of natural compounds, immunotherapy and inhibitors of yeast adherence factors, are also discussed.