Prolonged eosinophilia caused by Strongyloidiasis in a patient with rheumatoid arthritis treated with upadacitinib

Rheumatoid arthritis (RA) is a systemic disease, which is caused by dysregulation of the immune system in the 'susceptible' persons, making them immunocompromised and prone to infections during the course of their disease. The majority of RA patients are being treated with immunosuppressive drugs which render them even more immunocompromised. We present a Caucasian patient living in South-eastern Europe who developed prolonged eosinophilia during the treatment of RA with upadacitinib. After a comprehensive work-up, she was diagnosed with strongyloidiasis, although she was living in non-endemic region of the world. We emphasise the importance of regular follow-up for immunocompromised patients and raise awareness of not only typical but also atypical infections that can occur during the course of the disease.