Clinical features of IgA vasculitis
Immunoglobulin A (IgA) vasculitis affects small blood vessels, producing a leukocytoclastic vasculitis1. Immunoglobulin A immune-complex deposits affect small vessels in the skin, gastrointestinal tract and kidney and the most significant potential consequence is vasculitic IgA nephritis. The classic clinical manifestations of IgA vasculitis areKaradag, 2019:
- nonthrombocytopenic palpable purpura—typically on the lower limbs extending to the buttocks, occurring in almost all patients
- colicky abdominal pain—due to vasculitis of the bowel wall
- arthritis—typically only affecting a few large joints, commonly in the lower limbs, associated with significant pain and swelling that usually resolves within daysKaradag, 2019
- nephritis—often delayed, ranging from mild to severe.
Vasculitic IgA nephritis is mediated by IgA immune-complex deposits in the glomerulus. It can occur up to 6 months after the initial presentation of IgA vasculitis, but most cases present within 3 months. The nephritis is usually self-limiting and resolves fully over weeks to months.
If severe glomerular inflammation occurs, it can lead to permanent scarring of the kidney(s), which occasionally progresses to chronic or even end-stage kidney disease. Progression to chronic kidney disease is most likely to occur in people who present with a mixed nephritic–nephrotic syndrome, or nephrotic syndrome. Chronic kidney disease can occur shortly or even years after an apparent full recovery.