What Is Henoch-Schönlein Purpura Nephritis?
Henoch-Schönlein purpura (HSP) is a relatively common autoimmune condition often encountered in dermatology, though its effects extend far beyond the skin. At its core, HSP is a form of small-vessel vasculitis—an inflammation of the blood vessels—triggered by an abnormal immune response. While it frequently presents with visible skin symptoms such as purple rashes, particularly on the lower extremities, it can also impact multiple organ systems throughout the body.
Understanding the Different Types of HSP
Depending on which organs are affected, HSP manifests in several distinct forms. When the gastrointestinal tract becomes involved, it's referred to as abdominal or gastrointestinal HSP, often causing abdominal pain, nausea, and even gastrointestinal bleeding. If joint inflammation occurs, patients may develop arthralgia or arthritis, known as arthritic-type HSP. However, one of the most concerning complications arises when the kidneys are affected—this is known as HSP nephritis, or more commonly, Henoch-Schönlein purpura nephritis.
What Happens When the Kidneys Are Involved?
HSP nephritis indicates that the immune-mediated inflammation has reached the kidneys, potentially damaging the glomeruli—the tiny filtering units responsible for removing waste from the blood. This renal involvement can range from mild to severe and requires careful monitoring and management. One of the earliest signs is abnormalities in urinalysis, including proteinuria (excess protein in the urine) and hematuria, particularly non-uniform red blood cells, which suggest glomerular damage.
Symptoms and Clinical Indicators of Kidney Damage
In addition to urinary changes, patients may exhibit systemic signs of kidney dysfunction. Blood tests might reveal elevated lipid levels (hyperlipidemia) or decreased serum albumin, reflecting significant protein loss through the urine. The severity of proteinuria varies—some individuals experience only trace amounts, while others progress to heavy protein loss consistent with nephrotic syndrome, a serious kidney disorder characterized by massive proteinuria, low blood protein, high cholesterol, and swelling (edema).
Treatment Approaches Based on Disease Severity
When HSP nephritis reaches nephrotic levels, treatment strategies shift accordingly. Management often mirrors that of primary nephrotic syndrome and may include corticosteroids, immunosuppressive agents, and supportive therapies like ACE inhibitors to reduce protein leakage and protect kidney function. Early diagnosis and intervention are crucial to prevent long-term kidney damage or progression to chronic kidney disease.
While many cases of HSP resolve spontaneously, especially in children, renal involvement necessitates a more proactive medical approach. Regular follow-ups with urine testing and blood work are essential to monitor recovery and detect any persistent or recurring kidney issues. With appropriate care, the majority of patients achieve remission, though a small percentage may face ongoing renal challenges.