What Is Henoch-Schönlein Purpura Nephritis?

Henoch-Schönlein purpura nephritis (HSPN) is a form of kidney inflammation that develops as a complication of Henoch-Schönlein purpura (HSP), an autoimmune condition characterized by small blood vessel inflammation. This condition primarily affects children but can also occur in adults, typically following an upper respiratory infection or immune system trigger.

Understanding the Link Between HSP and Kidney Damage

HSPN arises when immune complexes—particularly those containing immunoglobulin A (IgA)—deposit in the glomeruli, the filtering units of the kidneys. This deposition leads to inflammation and damage, impairing the kidney's ability to filter waste and excess fluids effectively. While skin manifestations such as purplish rashes (typically on the legs and buttocks), joint pain, abdominal discomfort, and gastrointestinal bleeding are hallmark signs of HSP, renal involvement usually appears within 4 to 8 weeks after the initial symptoms.

Common Symptoms of HSP-Related Kidney Involvement

The earliest signs of kidney dysfunction in HSP patients often include microscopic hematuria (blood visible only under a microscope) or intermittent gross hematuria (visible blood in urine). Proteinuria, or the presence of excess protein in the urine, is another key indicator. In more severe cases, patients may develop hypertension, edema (swelling in the legs or face), and reduced kidney function. If left untreated, a subset of individuals—especially those with persistent proteinuria—may progress toward chronic kidney disease.

Diagnosis and Medical Evaluation

Diagnosing HSPN involves a combination of clinical history, urinalysis, blood tests, and sometimes a kidney biopsy. Urine tests typically reveal red blood cells and protein, while blood work may show elevated inflammatory markers. A kidney biopsy remains the gold standard for assessing the extent of glomerular injury and guiding treatment decisions, particularly in moderate to severe cases.

Treatment Approaches and Prognosis

The majority of HSPN patients have a favorable prognosis, especially children with mild urinary abnormalities. Management often begins with supportive care, including blood pressure control using ACE inhibitors or ARBs, which also help reduce proteinuria. For patients with more aggressive disease—such as nephrotic-range proteinuria or rapidly declining kidney function—immunosuppressive therapies like corticosteroids or other agents may be considered.

Lifestyle modifications, regular monitoring of kidney function, and early intervention play crucial roles in preventing long-term complications. With timely diagnosis and appropriate management, most individuals recover fully without lasting kidney damage. However, ongoing follow-up is recommended, as some patients may experience late recurrences or subtle progression over time.

Prevention and Awareness

While there is no guaranteed way to prevent HSPN, recognizing the early signs of HSP and seeking prompt medical attention can significantly reduce the risk of kidney complications. Educating parents, caregivers, and healthcare providers about the potential renal consequences of HSP enhances early detection and improves patient outcomes.