Nephrotic syndrome is a rare kidney disorder that causes high levels of protein in the urine (proteinuria) and low levels of protein in the blood. It may cause high cholesterol and swelling around the eyes, legs, and feet.

Symptoms of nephrotic syndrome include loss of appetite, unexpected weight gain, abdominal (belly) pain, and weakness.

Common causes of nephrotic syndrome include kidney diseases as well as other diseases and conditions that affect the kidneys, including diabetes, systemic lupus erythematosus (SLE), and hepatitis C. Allergic reactions to insect bites, poisonous plants, and medicines can also lead to nephrotic syndrome.

Nephrotic syndrome can affect both adults and children. It can often be cured by removing or treating the cause (for instance, stopping use of a medicine). If the cause is not treatable or is not known, medicines may be used to reduce the symptoms of nephrotic syndrome. If the problem causing nephrotic syndrome is not corrected, the disorder can progress to kidney failure.