P44 | Advanced diagnostic approaches in unexplained hyper-eosinophilia: navigating the challenges of parasitic infections

M. Colorato¹, A. Aceranti¹, S. Vernocchi¹, C. Simoni², C. Celesia², L. Maroni², V. D’Ambrosio², S. Limbiati², F. Staffa², T. Kosmos³ | ¹Istituto Europeo di Scienze Forensi e Biomediche, Milano, ²Ospedale di Gallarate, ASST Valle Olona (VA), ³Ospedale di Busto Arsizio, ASST Valle Olona (VA), Italy

Background: Hyper-eosinophilia signals various pathological processes, including allergic or autoimmune reactions, and notably, parasitic infections.
Case report: We present four cases of hypereosinophilia due to parasitosis, diagnosed only after extensive diagnostic processes, involving at endoscopic investigations or invasive explorations. Eosinophilia with persistent systemic symptoms and inflammation, remained unexplained by standard tests for parasitic infections. This highlights the importance of a more comprehensive, and sometimes invasive, diagnostic approach. Endoscopic investigations and biopsies revealed the presence of parasites that were undetected in conventional fecal or serological tests. These included species such as Toxocara, Entamoeba histolytica, Enterobius vermicularis, and Giardia lamblia, known for their ability to evade standard diagnostic procedures. The necessity of invasive procedures became crucial in cases where clinical symptoms and persistent eosinophilia found no explanation through non-invasive investigations. Definitive diagnosis was possible only through repeated endoscopies or tissue biopsies. These cases underscore the importance of not overlooking the possibility of parasitosis in case of eosinophilia and persistent symptoms and negative tests should not stop investigations with invasive methods.
Conclusions: The clinical experience derived from these cases emphasizes the importance of a invasive diagnostic approach in the presence of hyper-eosinophilia, in order to rule out or confirm parasitic infections that may elude standard diagnostic methods.