Schönlein-Henoch Purpura: Causes

Pathogenesis (disease development)

It is likely that Schönlein-Henoch purpura is a genetic-based immunopathologic reaction triggered by various triggers (elicitors), such as infections or medications. The disease is often preceded by an upper respiratory tract infection. In half of the cases, this is influenza A (flu/viral illness).

The allergic immune complex reaction is classified as a “type III allergy” (synonyms: type III allergy, immune complex type allergy, type III hypersensitivity reaction, immune complex type, Arthus type). After contact with the allergen, immune complexes (allergen + antibodies) are formed within hours. The IgA-containing immune complexes are deposited subendothelially (below the endothelium/cells of the innermost wall layer facing the vessel lumen) in the small vessels. The complement system is activated, i.e. phagocytosis (uptake of foreign substances by scavenger cells) of the immune complexes by leukocytes (white blood cells) occurs.

Pathophysiolgically, the disease is based on leukocytoclastic vasculitis or proliferative glomerulonephritis with IgA deposition.

Etiology (Causes)

Behavioral causes

  • Diet
    • Food Allergens

Causes due to disease

  • Influenza A (flu/viral illness).
  • Parvovirus infections, e.g., ringworm (erythema infectiosum).
  • Streptococcal diseases (ß-hemolytic streptococci).
  • Varicella (chickenpox)

Medication