What causes recurrent episodes of allergic purpura?

The recurrence of Henoch-Schönlein purpura (HSP) can be attributed to various factors, primarily including: 1. Immune system dysregulation: HSP is an autoimmune disease. When the immune system is abnormally activated, it may mount an immune response against the body's own tissues, leading to recurrent episodes of purpura. 2. Infections: Bacterial and viral infections—such as influenza, adenovirus, and Mycobacterium tuberculosis—often act as triggers for HSP. Re-infection during the course of illness or after recovery may exacerbate symptoms or lead to relapse. 3. Food allergies: Certain foods, such as milk, fish, and nuts, may provoke allergic reactions in susceptible individuals, potentially triggering a recurrence of purpura. 4. Other factors: Environmental influences, genetic predisposition, dietary irregularities, and psychological stress may also contribute to the repeated occurrence of HSP. The causes of recurrent HSP are complex and require comprehensive evaluation of multiple factors, along with appropriate therapeutic interventions.