Gastrointestinal bleeding as an early presentation of the pediatric granulomatosis with polyangiitis: A rare report.

Granulomatosis with polyangiitis is a rare autoimmune disorder. Granulomatosis with polyangiitis's signs and symptoms reflect affected organs, which are inclined toward the respiratory tract and kidneys. Gastrointestinal involvement is uncommon and barely represents this disease, particularly as an initial presentation. Here, we describe a diagnostically challenging case of a 14-year-old boy whose first manifestation of granulomatosis with polyangiitis was gastrointestinal bleeding, initially resembling immunoglobulin A vasculitis. Despite overlapping features such as arthralgia and skin lesions, renal biopsy, and cytoplasmic antineutrophil cytoplasmic antibodies positivity distinctly established granulomatosis with polyangiitis diagnosis. Recognizing gastrointestinal manifestations as potential indicators of granulomatosis with polyangiitis, even when hallmark respiratory symptoms are absent, enhances vigilance, and is crucial for early diagnosis and appropriate management.