An 8-Year-Old Female with Giardiasis-Associated Henoch-Schönlein Purpura: A Case Report and Literature Review.

Background and Clinical Significance: Henoch-Schönlein purpura (HSP), also known as Immunoglobulin A (IgA) vasculitis (IgAV), is a common systemic vasculitis in children characterized by palpable purpura, abdominal pain, and joint and kidney involvement. While respiratory tract viral or bacterial infections are the most common causes of HSP, parasitic infections, such as giardiasis, are occasionally reported. Giardia lamblia is the most common parasite infecting humans and a major cause of infectious diarrhea, which can lead to post-infection complications. To our knowledge, this is the first report in Greece describing a pediatric patient with HSP secondary to giardiasis. A review of pediatric HSP cases caused by parasitic infections is also included. Case presentation: An 8-year-old girl presented with a purpuric rash, joint tenderness, severe abdominal pain, and bloody diarrhea, raising suspicion of HSP. Laboratory tests revealed elevated IgA levels, and stool analysis tested positive for Giardia lamblia antigen. The diagnosis of HSP secondary to giardiasis was confirmed, and the patient was successfully treated with supportive care, metronidazole, and corticosteroids. Conclusion: This case report and literature review highlight parasitic infections as an underrecognized but important trigger of pediatric HSP. Although giardiasis is linked to various post-infectious complications, its association with HSP is rarely reported. Pediatricians should maintain a high level of suspicion for underlying infectious diarrhea, such as giardiasis, in patients with HSP, especially in children with prominent gastrointestinal symptoms. Early recognition can reduce complications and facilitate faster recovery. Further research is needed for the immunopathogenic mechanisms linking parasitic infections and HSP in children.