Malessezia pachydermatis is an important pathogen in veterinary medicine.[14] It has been known to become pathogenic to its host causing otitis and seborrhoeic dermatitis.[4] First associated with canine otitis externa in 1955 by Benght A. Gustafson, this yeast has since become an important pathogen especially in the study of small animal medicine. Symptoms include excessive scratching, head shaking, odour, and reddish-brown waxy deposits within the ear canal.[3] Malassezia pachydermatis caused canine seborrhoeic dermatitis was first discovered by Dufait in 1975 and may be characterized by symptoms ranging from dandruff to scaly lesions. At infection sites sebaceous secretions are increased.[3] Differences to susceptibility can be seen across breeds for example, increased infection among the West Highland White Terrier has been attributed to a genetic abnormality.[3]
Low pH environments have been associated with antimicrobial activity and dogs have among the highest skin pH levels of any domesticated animal. Malassezia pachydermatis is most commonly isolated from areas of the skin and ears with higher pH levels. Therefore canine colonization may occur more readily due to the skins increased alkalinity.[14] Samples have been collected from the ears, skin, vagina, and anal sacs.[9] Canine infection often co-occurs with atopy and other allergic disorders.[13][15] In contrast, felines are rarely infected by M. pachydermatis but when Malassezia spp. dermatitis does occur, it is not typically associated with any other conditions