Vital corner of diagnostic challenge: eosinophilic granulomatosis with polyangiitis or COVID-19 pneumonia?

The COVID-19 pandemic raises many alarms in the rheumatological era. Gianfrancesco et al reported the answer of an important question: the characteristics associated with hospitalization for COVID-19 in people with rheumatic disease.1 The data suggested that patients with rheumatic disease on prednisone dose of ≥10 mg/day were associated with higher odds of hospitalization, and vasculitis was the fourth common rheumatic disease among all of these patients. Another essential concept is to be careful in the differential diagnosis of the patients presenting with symptoms and signs of COVID-19. Physicians should keep in mind the other infectious and inflammatory diseases during diagnostic procedures of these critical patients. Inevitably, COVID-19 ranks first in differential diagnosis of all patients with respiratory symptoms and signs in current pandemic days. The standard of reference for confirming COVID-19 relies on microbiological tests, such as real-time reverse transcription polymerase chain reaction (RT-PCR).2 A systematic review of the accuracy of COVID-19 tests reported false-negative rates up to 29% (equating to a sensitivity of 71–98%), based on negative RT-PCR tests which could turn out positive on repeated testing.3 Chest CT can be used as an auxiliary to RT-PCR for diagnosing COVID-19 pneumonia in the current pandemic context.4 The main CT feature of COVID-19 pneumonia is the bilateral patchy ground-glass opacities (GGOs) with peripheral predominance.5 On the other hand, GGO has many causes and one of these is eosinophilic granulomatosis with polyangiitis (EGPA). Herein, we presented two patients who have been hospitalized with preliminary diagnosis of COVID-19 but diagnosed as EGPA in hospitalisation period for COVID-19. A male patient in his 20s was admitted to the emergency department with complaints of shortness of breath, cough and sputum. In the medical history of the patient, he had asthma for 3 years but he did not receive any asthma …