Cutaneous involvement in canine leishmaniosis due to Leishmania infantum (syn. L. chagasi).

BACKGROUND: Canine leishmaniosis, a zoonotic infectious disease caused by Leishmania infantum (syn. L. chagasi), is fairly common in endemic areas, and skin lesions are the most frequent clinical manifestation. Despite the large volume of relevant scientific information, there is a relative paucity of up-to-date review articles on the cutaneous manifestations of the disease. HYPOTHESIS/
OBJECTIVES: This review provides current information on the macroscopic and histological skin lesions of dogs with leishmaniosis and comments on their pathogenesis and definitive diagnosis.
METHODS: Published articles have been thoroughly reviewed and the retrieved information has been used and supplemented as appropriate with the authors' clinical experience.
RESULTS: The main clinicopathological presentations of canine leishmaniosis are exfoliative, ulcerative, nodular, sterile pustular and papular dermatitis and nodules at the site of parasite inoculation. Histopathology is usually dominated by mononuclear inflammatory infiltrates; immunohistochemical findings are variable, and Leishmania amastigotes are present in both diseased and normal-looking skin of dogs with leishmaniosis. Definitive diagnosis of the skin lesions in a dog with leishmaniosis is based on their macroscopic appearance, exclusion of main differentials, histopathology, demonstration of the parasite in the skin and complete response to antileishmanial treatment. CONCLUSIONS AND CLINICAL IMPORTANCE: Canine leishmaniosis due to L. infantum is characterized by diverse cutaneous manifestations that may reflect different host-parasite relationships. Furthermore, different types of skin lesions may occur, in various combinations, in the same dog. The definitive diagnosis of these lesions is based on clinical and laboratory examinations and on the response to antileishmanial treatment.