Factors associated with the occurrence of epistaxis in natural canine leishmaniasis (Leishmania infantum)

Background: Canine leishmaniasis (CanL) is a common cause of epistaxis in dogs residing in endemic areas. The pathogenesis of CanL-associated epistaxis has not been fully explored because of the limited number of cases reported so far. Hypothesis: Epistaxis in CanL could be attributed to more than 1 pathomechanism such as hemostatic dysfunction, biochemical abnormalities, chronic rhinitis, and coinfections occurring in various combinations. Animals: Fifty-one dogs with natural CanL. Methods: The allocation of 51 dogs in this cross-sectional study was based on the presence (n = 24) or absence (n = 27) of epistaxis. The potential associations among epistaxis and concurrent infections (Ehrlichia canis, Bartonella spp., and Aspergillus spp.), biochemical and hemostatic abnormalities, and nasal histopathology were investigated. Results: Hypergammaglobulinemia (P = .044), increased serum viscosity (P =.038), decreased platelet aggregation response to collagen (P = .042), and nasal mucosa ulceration (P =.039) were more common in the dogs with epistaxis than in those without epistaxis. The other significant differences between the 2 groups involved total serum protein (P = .029) and gamma-globulin (P = .013) concentrations, which were higher, and the percentage platelet aggregation to collagen, which was lower (P = .012) in the epistaxis dogs. Clinical Importance: CanL-associated epistaxis appears to be the result of multiple and variable pathogenetic factors such as thrombocytopathy, hyperglobulinemia-induced serum hyperviscosity, and nasal mucosa ulceration.