Lupus nephritis can cause foamy urine, blood in the urine, swelling around the feet, ankles, legs, hands, or eyes, and high blood pressure. Some people need to urinate more often, especially at night. However, kidney inflammation may cause no noticeable symptoms early on, so people with lupus can have kidney changes even when they feel well. Urine and blood tests can help detect these changes.
Which symptoms can lupus nephritis cause?
Lupus nephritis is kidney inflammation caused by systemic lupus erythematosus (SLE), an autoimmune disease in which the immune system attacks the body's own tissues. The resulting inflammation can affect how well the kidneys filter waste and remove extra fluid from the blood. According to Mayo Clinic, signs of lupus nephritis can include changes in urine, swelling, and high blood pressure. The specific symptoms depend on how the kidneys are affected, and some people do not notice any changes at first.
- Foamy or unusually bubbly urine: Urine may appear persistently foamy when excess protein passes from the blood into the urine because of kidney damage.
- Blood in the urine: Blood may make urine look pink, red, or brown. However, the amount can be too small to see and may only be detected by a urine test.
- Swelling around the eyes or in the face: Fluid can collect in tissues, making the area around the eyes appear puffy, sometimes particularly noticeable after waking.
- Swelling in the feet, ankles, or legs: Extra fluid may build up in the lower body. Swelling can also affect the hands or other areas.
- High blood pressure: Blood pressure may rise when the kidneys are affected. High blood pressure often causes no obvious symptoms, so measuring it is more reliable than judging it by how someone feels.
- Changes in urination: Some people may need to urinate more frequently than usual, including during the night. A noticeable reduction in the amount of urine can also be concerning, particularly when kidney function is deteriorating.
Can lupus nephritis develop without noticeable symptoms?
Yes. Lupus nephritis may begin without clear changes in how a person feels or urinates. According to the Lupus Foundation of America, people may not notice symptoms during the early stages. Kidney inflammation can therefore be present even when someone feels well and has no visible swelling or obvious urine changes.
This is why routine kidney monitoring matters for people living with lupus. Urine tests can detect protein or blood that cannot be seen, while blood tests help assess how well the kidneys are filtering waste. Regular checks may identify changes before noticeable symptoms develop.
What other symptoms may occur alongside lupus nephritis?
Lupus can affect several parts of the body, so kidney involvement may occur alongside symptoms elsewhere. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) describes symptoms that may accompany lupus-related kidney problems, including joint pain or swelling, muscle pain, fever without a known cause, and a red facial rash that may cross the nose and cheeks.
These symptoms reflect possible lupus activity throughout the body rather than specific signs of kidney inflammation. Their presence does not establish whether the kidneys are affected, and their absence does not rule out lupus nephritis. Kidney-specific assessment is important when clinicians evaluate possible renal involvement.
What symptoms can occur if kidney function becomes more affected?
When kidney function declines significantly, waste products and extra fluid may build up in the body. In addition to swelling and changes in urination, a person may experience persistent tiredness, nausea, vomiting, reduced appetite, itching, or difficulty concentrating. The Lupus Foundation of America identifies these as possible symptoms of kidney failure in people with lupus nephritis.
These symptoms are not specific to lupus nephritis and can occur with other health problems. Their significance depends on the person's overall health, kidney function, medical history, and findings from clinical assessment. New or worsening symptoms should be discussed with a healthcare professional rather than attributed automatically to lupus.
When should you seek medical advice?
People living with lupus should contact their healthcare professional if they notice new or persistent foamy urine, visible blood in the urine, unexplained swelling, changes in urination, or blood pressure that is higher than usual. These changes can have several causes, but they warrant assessment when kidney involvement is a concern.
Seek urgent medical attention for a sudden, substantial reduction in urine output, rapidly increasing swelling, or difficulty breathing. These problems can indicate a significant medical issue that needs prompt evaluation, even if the cause is not yet known.
If lupus nephritis has already been diagnosed, report new symptoms or a noticeable change from your usual condition to the treating team. Symptoms can change over time, and the significance of a change depends on the person's kidney function and overall clinical situation.
How do healthcare professionals check for lupus nephritis?
Symptoms alone cannot confirm or exclude kidney inflammation. Healthcare professionals consider a person's lupus history, current symptoms, physical examination, blood pressure, and test results. According to MedlinePlus Medical Encyclopedia, the assessment may include urine testing for blood and protein, blood tests to evaluate kidney function, and, when appropriate, a kidney biopsy to examine kidney tissue.
Urine testing is particularly useful because kidney changes may be detectable even when no symptoms are present. Blood tests commonly measure creatinine, a waste product used to assess how well the kidneys filter the blood. A kidney biopsy may help confirm lupus nephritis and determine the pattern of kidney involvement when the clinical team considers it necessary.
For people who have lupus, the healthcare professional determines an appropriate monitoring schedule based on their medical history, previous results, current condition, and treatment. Testing is important even when there are no obvious symptoms because early recognition of kidney involvement can help guide care.