Lupus nephritis, or kidney lupus, most often develops within the first five years after the symptoms of lupus start and usually affects people between the ages of 20 and 40. It’s estimated that as many as 40 percent of all people with lupus – and as many as two-thirds of all children with lupus – will develop kidney complications that require medical evaluation and treatment – making kidney lupus an important aspect of lupus to understand.
When lupus affects the kidney, often there are no symptoms. Generally the diagnosis is made because urine testing shows positive protein in the urine. When the amount of protein is quantified there is greater than normal amounts of protein being excreted. Sometimes leg swelling (edema) occurs. At other times a lupus patient knows they are ill for various reasons-rash, joint pain, fever, etc, and kidney lupus turns out to be part of the flare. Read more.