Abstract
The evaluation of acute abdominal pain remains diagnostically challenging, particularly in adolescent females, where
gynecologic and systemic causes must be considered. Immunoglobulin A vasculitis (IgAV) can initially manifest with
isolated gastrointestinal symptoms, making early recognition difficult when the classical triad of purpura, arthritis,
and abdominal pain is incomplete. We report a case of IgAV in a 16-year-old girl who presented solely with abdominal
pain. Imaging showed terminal ileal thickening, but no definitive etiology. Continued inpatient observation and
hypothesis-driven physical examination (HDPE) revealed new-onset purpura and arthritis on hospital day 8. A skin
biopsy of the purpuric lesions confirmed the diagnosis, showing leukocytoclastic vasculitis with perivascular neutrophilic
and eosinophilic infiltration on histology and IgA deposition on immunofluorescence. This case underscores
the importance of HDPE and serial reassessment in diagnostically ambiguous cases of acute abdomen. Importantly, it
highlights the diagnostic utility of skin biopsy in confirming vasculitis, particularly when extra-abdominal features
appear late in the clinical course. Early discharge could have led to delayed or missed diagnosis. Clinicians should
maintain vigilance for evolving systemic signs in similar presentations and be aware that purpura and arthritis may
emerge only after a significant delay from the initial gastrointestinal symptoms.
