How to diagnose and treat demodicosis in dogs

Abstract

BACKGROUND AND OBJECTIVES: These guidelines were written by an international group of specialists with the aim to provide veterinarians with current recommendations for the diagnosis and treatment of canine demodicosis. METHODS: Published studies of the various treatment options were reviewed and summarized. Where evidence in form of published studies was not available, expert consensus formed the base of the recommendations. RESULTS: Demodicosis can usually be diagnosed by deep skin scrapings or trichograms; in rare cases a skin biopsy may be needed for diagnosis. Immune suppression due to endoparasitism or malnutrition in young dogs and endocrine diseases, neoplasia and chemotherapy in older dogs are considered predisposing factors and should be diagnosed and treated to optimize the therapeutic outcome. Dogs with disease severity requiring parasiticidal therapy should not be bred. Secondary bacterial skin infections frequently complicate the disease and require topical and/or systemic antimicrobial therapy. There is good evidence for the efficacy of weekly amitraz rinses and daily oral macrocyclic lactones such as milbemycin oxime, ivermectin and moxidectin for the treatment of canine demodicosis. Weekly application of topical moxidectin can be useful in dogs with milder forms of the disease. There is some evidence for the efficacy of weekly or twice weekly subcutaneous or oral doramectin. Systemic macrocyclic lactones may cause neurological adverse effects in sensitive dogs, thus a gradual increase to the final therapeutic dose may be prudent (particularly in herding breeds). Treatment should be monitored with monthly skin scrapings and extended beyond clinical and microscopic cure to minimize recurrences.