A Case of Human Subcutaneous Dirofilariasis Presenting as Urticaria

Human subcutaneous dirofilariasis (HSD) is a rare zoonotic infection caused by worms of the genus Dirofilaria. We report a case of a 43-year-old gentleman who presented with itchy and erythematous wheals associated with a swelling of the left arm. Ultrasound examination of the left arm showed a hypoechoic lesion measuring 1.2 x 0.4 cm in subcutaneous plane with internal tubular serpiginous structure suggestive of subcutaneous filariasis. The swelling was excised and histopathological examination revealed a granulomatous lesion surrounding a worm belonging to the species D. repens. We present this case to highlight the importance of considering a diagnosis of human subcutaneous dirofilariasis in patients presenting with urticaria, especially if associated with subcutaneous nodules.

Automated summary

Human subcutaneous dirofilariasis is a rare zoonotic infection caused by worms of the genus Dirofilaria. This case presented with itching, erythematous wheals, and swelling, with ultrasound examination revealing a hypoechoic lesion with internal tubular serpiginous structure.