I have got you under my skin

Excerpt

Early in November 2019, a 67-years old colleague, returning from 1-month fellowship in a rural hospital in the North of Ethiopia, was referred to our Infectious Diseases Unit for the recent appearance of a palpable lump on his right forearm associated to intense generalized pruritus. His past medical history was unremarkable except for seasonal rhinitis well controlled by on-demand antihistamines. During his time in Ethiopia, he remains free of any symptom but for a circumscribed arm swelling that progressed slowly in the following weeks. Furthermore, generalized pruritus started at the end of October and required medical consultation. The lesion was evident at the time of the consultation, appearing as a 20 mm swelling with intact superficial skin with no redness, warmness or pain. Baseline blood analysis showed a normal leukocyte count (5330 cells/µL) without eosinophilia (1.5%, 80 cells/mm³). All other laboratory parameters, including total IgE levels (IgE 58 kUI/L, standard value ≤ 100 kUI/L), were within reference ranges. Ultrasonography found a well-circumscribed lesion, measuring 11 × 7 × 10 mm, without twinkling artifacts or movements within the cystic lesion (Fig. 1a). Microscopic evaluation of three stool samples collected on different days and blood specimens for microfilariae detection, as well as serologies for Strongyloides spp, Trichinella spp., and Echinococcus spp. resulted negative. The nodule was excised under local anesthesia, and parasitological examination confirmed the presence of Dirofilaria repens (Fig. 1b–d). Human dirofilariasis is currently considered an emerging mosquito-borne zoonosis caused by filarial worms of the genus Dirofilaria [1]. Adults D. repens, the most significant Dirofilaria coupled with D. immitis, are commonly located in subcutaneous tissues, and the approach is primarily surgical [2]. D. repens is currently found in Europe, Asia, and Africa, but has recently spread into colder regions [2, 3]: we are facing a continuous increase in the risk for humans to acquire dirofilariasis, because of climate changes, frequent travel and more extensive distribution of vectors outside tropical settings [3, 4].

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