Pediatric Granulomatosis With Polyangiitis Mimicking IgA Vasculitis: A Case Report.

Background: Granulomatosis with polyangiitis (GPA) is a systemic vasculitis of the upper and lower respiratory tract along with glomerulonephritis and is very rare in childhood. Its renal manifestations similarity with IgA vasculitis can be misleading.

Case presentation: Herein, we report a 12-years-old girl with the clinical picture of IgA vasculitis and renal involvement at the time of presentation, over time, elevated cytoplasmic Anti-neutrophil Cytoplasmic Antibody (C-ANCA) and tissue biopsy confirmed GPA.

Conclusion: In the case of a patient with an unusual presentation of IgA vasculitis, to some degree of suspicion, the GPA should be considered. Also, in approach to non-thrombocytopenic palpable petechia and purpura a wide range of differential diagnosis such as infections, ANCA associated vasculitis, and secondary vasculitis should be considered. Therefore, 2 effective method of GPA diagnosis, the high titer of C-ANCA test and tissue biopsy, should be considered simultaneously.