Unmasking the Unknown

Dirofilariasis is a disease involving the parasitic nematode Dirofilaria and is an emerging zoonotic disease with limited awareness among health care providers. It is mainly transmitted to humans from mammalian hosts through mosquito vectors. The disease is more prevalent in countries with tropical, sub-tropical, and temperate weather, but due to more widespread travel involving humans and pets, the incidence and prevalence have been on the rise worldwide. Due to decreased awareness among clinicians and inherent difficulties with diagnosis, Dirofilariasis continues to be underdiagnosed. Humans, as dead-end hosts, usually have more benign presentations, commonly in subcutaneous, pulmonary, and ocular locations. The incidental discovery of a nodule of unknown etiology, particularly in internal organs or atypical locations, often raises significant concern, potentially prompting extensive diagnostic evaluations. This can be time-consuming, resource-intensive, and may result in unnecessary interventions. We present the case of a subcutaneous scalp nodule that failed treatment with antibiotics. Following surgical excision, pathology revealed a parasite that was morphologically consistent with Dirofilaria.