Evaluation of the potential causes of epistaxis in dogs with natural visceral leishmaniasis.

Haemostasis was evaluated in 19 dogs with natural Leishmania infection, six of them with a history of epistaxis, and the results were compared with the results from 24 healthy dogs. In addition, the dogs' blood pressure was measured and biopsies were taken from the nasal mucosa. Buccal mucosa bleeding time was prolonged in the dogs with leishmaniasis (P < 0.002) and most significantly in those with epistaxis (P < 0.005). None of the Leishmania-infected dogs had thrombocytopenia, low levels of plasma von Willebrand factor antigen, a prolonged prothrombin time or activated partial thromboplastin time, a low plasma fibrinogen concentration or high serum fibrin degradation products. These results rule out defects of secondary haemostasis or disseminated intravascular coagulation as significant causes of epistaxis in non-complicated leishmaniasis. Histopathology of the nasal mucosa of 10 of the affected dogs, three of them with epistaxis, revealed ulcerative and inflammatory lesions in all of them.