Multisystemic eosinophilic epitheliotropic disease subsequent to parasitic lymphadenopathy in a mare

Multisystemic eosinophilic epitheliotropic disease is an uncommon chronic condition in horses, which is characterised by eosinophilic infiltration of the intestine and other organs. Clinical signs usually reported are weight loss, intermittent diarrhoea and generalised dermatitis. The aetiopathogenesis is not fully understood, but intestinal nematodes were strongly suspected to play a role by several authors. We describe the clinical and histopathological findings, treatment and progression of a mare with a presumptive diagnosis of multisystemic eosinophilic epitheliotropic disease in which a larva migrans was identified in a reactive lymph node approximately a year before the development of symptomatology suggestive of multisystemic eosinophilic epitheliotropic disease. After the first assessment, moxidectin and ivermectin were administered at 30 days of interval, and the owner reported that no further signs were observed for approximately 8 months, when it started to note weight loss, dermatitis and oral ulceration. This report may support the role of parasitic migration in the pathogenesis of multisystemic eosinophilic epitheliotropic disease.