Chronic polyarthritis as isolated manifestation of toxocariasis

Human toxocariasis is a parasitic zoonosis mainly caused by Toxocara canis or Toxocara cati and is acquired by ingestion of the parasite's embryonated eggs. Arthralgia and/or arthritis were reported in up to 17% of the cases, generally with acute duration (less than 6 weeks). However, to our knowledge, chronic polyarthritis, as the isolated presentation of Toxocara infection, was not reported. One of the 5809 patients that was followed up at our service (0.017%) had chronic polyarthritis as the single manifestation of toxocariasis and was described herein. A 3-year-old girl was referred to our service with severe painful chronic polyarthritis for a period longer than 10 weeks and morning stiffness of 30min. Dog contact exposure history in the recreational areas of neighborhood was reported. Her exams showed high levels of eosinophils in peripheral blood (29%), bone marrow aspirate revealed marked eosinophilia (32%) and Toxocara enzyme-linked immunosorbent assay (Elisa) was positive (1:1280). She was treated with paracetamol (40mg/kg/day) and thiabendazole (25mg/kg/day) for 10 days, and all manifestations reduced. After eight months of follow-up, she was on clinical and laboratorial remission. In conclusion, we described a case of chronic polyarthritis, as isolated manifestation of toxocariasis, mimicking juvenile idiopathic arthritis and leukemia. Importantly, this zoonosis should be considered in patients with arthritis and eosinophilia.