© 2008 The Authors. Journal compilation © 2008 ESVD and ACVD. 20; 1–12 1 DOI: 10.1111/j.1365-3164.2008.00721.x Blackwell Publishing Ltd Evidence-based veterinary dermatology: a systematic review of interventions for Malassezia dermatitis in dogs Amélie Negre*, Emmanuel Bensignor† and Jacques Guillot‡ *Veterinary Clinic, 7 rue de l’Hôtel de Ville, le Châtelet-en-Brie, France †Veterinary Dermatology Referral Service, Veterinary Clinic, Paris and Cesson-Sévigné, Veterinary Hospital, Nantes, France ‡Department of Parasitology and Mycology, UMR INRA, AFSSA, ENVA BIPAR, Ecole Nationale Vétérinaire d’Alfort, Maisons-Alfort, France Correspondence: Jacques Guillot, ENVA, 94704 Maisons-Alfort, France, E-mail: jguillot@vet-alfort.fr Sources of Funding This study is self-funded. Conflict of Interest None to be declared. Abstract The aim of this systematic review was to evaluate the efficacy of antifungal treatments for Malassezia dermatitis in dogs and, when possible, to propose recommendation for or against their use. Electronic searches were carried out using PubMed MEDLINE®, CABDirect and CONSULTANT database. The volumes of Advances in Veterinary Dermatology, the proceedings of ESVD/ECVD and AAVD/ACVD con- gresses were hand-searched for studies relevant to this review. All articles and book chapters discussing treatment of Malassezia dermatitis were scanned for additional citations. Lastly, a request was sent to the Vetderm Listserv to share recent clinical trials. The analysis evaluated study design, methodology quality, subject enrolment quality, type of interventions and outcome measures. The searches identified 35 articles, and 14 trials that fulfilled the following selection criteria: (i) in vivo clin- ical trials, (ii) dogs showing clinical lesions of Malas- sezia dermatitis and (iii) enrolment of at least five dogs. Among these, only eight studies fulfilled the fol- lowing additional criterion: (iv) prospective in vivo clinical trials reporting clinical and mycological out- come measures. A total number of 14 different treat- ment protocols included four blinded, randomized and controlled trials (quality of evidence grade A), four controlled studies lacking blinding and/or randomiza- tion (grade B), five open uncontrolled trials (grade C) and one descriptive study (grade D). This systematic review allowed us to recommend, with good evidence, the use of only one topical treatment of Malassezia dermatitis (2% miconazole nitrate +2% chlorhexidine, twice a week for 3 weeks) and with fair evidence the use of two systemic treatments with azole derivatives (ketoconazole, 10 mg kg –1 day –1 and itraconazole, 5 mg kg –1 day –1 for 3 weeks). Accepted 10 March 2008 Introduction The lipophilic yeast Malassezia pachydermatis is part of the normal cutaneous microflora of many warm-blooded vertebrates. It is commonly found on healthy dogs in the ear canals, on the lips, axillae folds, interdigital spaces, anal sacs, rectum and less commonly in the nose and vagina. 1–4 This yeast may become a pathogen whenever alterations in the skin surface microclimate or host defence occur, and it is now widely accepted that Malassezia dermatitis is a common skin disease of dogs. The change in opinion in the importance of this disease in veterinary dermatology is illustrated by the number of articles on Malassezia dermatitis in the literature since the first description by Dufait in 1983. 5 Cases of zoonosis caused by M. pachydermatis have also been suspected. 6,7 Malassezia dermatitis can occur in dogs of any sex, age and breed with some breeds appearing to be predisposed, for example West Highland white terriers, Basset hounds, poodles, Australian silky terriers and American cocker spaniels. 1,5,8–10 Malassezia dermatitis in dogs may be localized or generalized. Skin lesions usually occur on the face (ear canal, perioral and periocular skin, ventral neck) or in cutaneous folds (axillae, groin, interdigital skin and claw folds). Clinical signs are variable: erythema, mild to severe pruritus, alopecia, greasy exudation and scaling are generally observed. Secondary lesions include excoriations, lichenification, hyperpigmentation and exudation. In generalized cases, an offensive and rancid odour is commonly reported. A reddish-brown staining of the claws is visible in case of Malassezia paronychia. Finally, otitis externa has also been associated with the presence of these yeasts. 1,11–14 The role of M. pachydermatis, as a pathogen, has been debated for a long time. Dufait, and then Mason, first established the yeast as a disease-causing agent. 5,15 The proliferation of yeasts is suspected to be promoted by excessive sebum production or disruption of the epidermal barrier such as may be occurring in hypersensitivity diseases (atopy, adverse cutaneous food reactions, flea bite hyper- sensitivity and contact allergy), cornification disorders, ectoparasite infection, bacterial pyoderma and endocrine diseases (hyperadrenocorticism, hypothyroidism, diabetes mellitus). 9 Long-term glucocorticoids may also increase Malassezia populations, 1,16 whereas all authors do not consider antibiotic administration as a predisposing factor. 10,17 Diagnostic criteria for Malassezia dermatitis in dogs are still not clearly defined. It has been proposed that the