Diagnosis and Laboratory Evaluation in IgA Vasculitis
Diagnosing IgA vasculitis requires a combination of clinical evaluation and laboratory testing. Because the disease can mimic other forms of vasculitis or autoimmune disorders, careful assessment is critical to confirm the diagnosis and rule out alternative conditions.
The initial step often involves recognizing the hallmark palpable purpura, particularly on the lower limbs. The presence of joint pain, abdominal symptoms, or renal involvement alongside the rash further supports the diagnosis. Clinicians consider patient age, recent infections, and family history during evaluation.
Laboratory tests provide additional confirmation. Urinalysis is essential to detect hematuria or proteinuria, indicating kidney involvement. Blood tests may reveal elevated inflammatory markers such as C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR), reflecting systemic inflammation. In some cases, blood counts help assess the overall impact on organ systems.
Immunological testing, including measuring IgA levels, can support the diagnosis, although elevated IgA alone is not definitive. The gold standard for confirming IgA deposition is biopsy of affected skin or kidney tissue. Histological examination typically shows leukocytoclastic vasculitis with IgA deposits in the vessel walls, confirming immune complex involvement.
Imaging studies are generally reserved for patients with severe gastrointestinal symptoms or suspected complications such as intussusception. Ultrasound or CT imaging can help evaluate intestinal involvement and guide urgent interventions.