Human dirofilariasis with reactive arthritis--case report and review of the literature.

A 43-year-old German man suffered from an insect bite, which was followed by a severe local inflammation and lymphadenitis. A year later, he developed dry cough, chest pain, and an oligoarthritis of the ankle and knee joints. While other causes of the symptoms could be excluded, serologic findings suggested a dirofilarial infection with reactive arthritis due to the parasite. The observation points out, that in cases of unclassifiable mono- or oligoarthritis, reactive arthritis due to parasites should be considered in the spectrum of differential diagnoses. The disease is rare at present, but its frequency might be underestimated because of the diagnostic difficulties. Dirofilarial infection should be borne in mind after a stay abroad. The present case, however, shows, that the disease also occurs in patients who had not travelled to regions of risk in recent years.