A number of features typify the presentation of IgA nephropathy. The hematuria may either be a single episode of gross hematuria, or recurrent episodes of gross hematuria with asymptomatic microscopic hematuria between episodes, or persistent asymptomatic microscopic hematuria. Episodes of hematuria are often associated with upper respiratory infections. By contrast, hematuria does not develop until 10- 14 days after pharyngitis in cases of classic acute glomerulonephritis. Other signs and symptoms include proteinuria, nephrotic syndrome, acute nephritis, malignant hypertension, chronic renal failure, and acute renal failure.
Proteinuria is typically within the mild range.
Findings on renal biopsy are characteristic. In all patients, IgA is present and is deposited mainly in the mesangium of the glomerular tuft. Other immunoglobulins and complement, especially C3, are often found in a mesangial pattern. Light microscopy frequently reveals a focal lesion, present in some but not all glomeruli. Electron microscopy will show a nodular electron dense deposit in either a subepithelial or subendothelial pattern.