How do you interpret significant eosinophilia in a patient with suspected granulomatosis with polyangiitis (GPA)?

This is an important question because at times the distinction between GPA and EGPA can be difficult to make. In general, I would rely on clinical symptoms as a key distinguisher. For example, sinusitis in GPA differs from that of EGPA, with the former often causing crusting, erosions/necrosis on EN...