IgA Vasculitis in an Adult Linked to Cryptosporidium and Giardia Co-Infection: A Comprehensive Case Study

BACKGROUND Immunoglobulin A (IgA) vasculitis is a small-vessel vasculitis characterized by the deposition of IgA immune complexes primarily in the skin, kidneys, and gastrointestinal tract. While it predominantly affects children, cases in adults are associated with more severe manifestations. Evidence suggests that infectious triggers play a pivotal role in its etiology. Often, it follows a self-limiting course and doesn't necessitate intervention. CASE REPORT We present the case of a 51-year-old man who presented with a maculopapular rash, arthralgia, and abdominal pain. An examination revealed a purpuric rash on lower extremities and abdomen. A lower extremity duplex ultrasound identified deep vein thrombosis (DVT) in the right leg. Skin biopsy of the rash confirmed the diagnosis of IgA vasculitis, demonstrating perivascular neutrophilic infiltrate and IgA complex deposition. Stool studies revealed co-infection with Cryptosporidium and Giardia. The patient was treated with a prednisone taper with significant improvement in symptoms. CONCLUSIONS This case highlights the potential role of Cryptosporidium as a trigger for IgA vasculitis. The presence of concurrent infections underscores the complex interplay between infections and the development of IgA vasculitis. The co-infection with Giardia suggests that a secondary infection may be involved, further complicating the disease's etiology. The observation of DVT suggests a possible link between IgA vasculitis and a prothrombotic state. This report serves to expand the knowledge of IgA vasculitis triggers and associated complications, guiding clinicians in diagnosing and managing similar cases while emphasizing the importance of vigilance in adults with these symptoms.