What is a key sign of nephritis in SLE patients?

In systemic lupus erythematosus (SLE), one of the critical manifestations that may develop is lupus nephritis, which affects the kidneys. A key sign of nephritis in SLE patients is proteinuria. This condition occurs when the kidneys are unable to filter proteins from the urine effectively, often resulting in elevated levels of proteins, particularly albumin. Proteinuria is significant because it indicates damage to the kidney's glomeruli, which can lead to further complications if not managed.

While other symptoms such as joint swelling, fatigue, and skin rashes are common in SLE, they do not directly indicate kidney involvement. Joint swelling may arise from inflammation due to SLE, fatigue can result from systemic disease activity, and skin rashes are typical of the condition overall but do not signal renal issues. Recognizing proteinuria as a sign of nephritis is crucial for early detection and treatment of renal complications in patients with systemic lupus erythematosus.