The epidemiological and clinical aspects of Demodex injai demodicosis in dogs: a report of eight cases

The mite Demodex injai causes demodicosis, an uncommon, chronic, and recurrent parasitic dermatopathy in dogs. Demodicosis is characterized by an excessive proliferation of the Demodex injai mite in the pilosebaceous unit. Typically, demodicosis occurs in adults, and is associated with an underlying disease or a specific host immunodeficiency. Here, we describe the epidemiological, clinical, dermatological, and therapeutic aspects of Demodex injai demodicosis in dogs (n=8) at the Hospital Unit for Companion Animals of the Pontifical Catholic University of Paraná in Brazil. The affected dogs were predominantly purebred, had a mean age of eight years, and showed no gender predisposition. The lesions were predominantly alopecic and erythematous-desquamatory, associated with follicular dyskeratosis and greasiness of the coat, and mainly affected the facial region, in addition to the back and limbs. The animals had a history of allergic, dyskeratotic, endocrine, neoplastic, and immunosuppressive comorbidities. The diagnosis of demodicosis was based on multiple skin scrapings, trichogram, and acetate tape impression of the lesion areas, macroscopic observation, and morphological characterization of the mite. Macrocyclic lactones were effectively used for treatment in most cases; however, improvement of the condition may be related to adjunctive treatment of the underlying disease.