Case report: Probable toxocariasis in a Swiss adult patient with hypereosinophilic syndrome and multiorgan involvement.

Hypereosinophilic syndromes are a heterogeneous group of rare diseases characterized by eosinophil-related organ damage and peripheral blood hypereosinophilia. Hypereosinophilic syndromes may occur secondary to a variety of clinical entities, for example, drug hypersensitivity reactions, parasitic infections, autoimmune disorders, and malignancies. Toxocariasis is a parasitic infection caused by the larval stage of the Toxocara species. It is usually a childhood disease and invades organs such as the liver but can affect any organ. Hypereosinophilic syndrome and multiorgan involvement are very rare manifestations of Toxocara infection, especially in adults. However, the disease may be underdiagnosed because of different factors, including a lack of laboratory infrastructure in some countries, a lack of uniform case definitions, and limited surveillance infrastructure, with its estimation constituting a challenge. We, therefore, present a probable case of hypereosinophilic syndrome with multiorgan involvement secondary to infection with Toxocara canis in a 79-year-old Swiss female patient with a medical history of ischemic cerebrovascular insult and a curatively resected non-small-cell bronchial carcinoma, successfully treated with albendazole and steroids.