Lupus nephritis is a condition that affects the kidneys of people with systemic lupus erythematosus — often simply called lupus. In lupus, a person’s immune system attacks different organs and body systems. People with lupus may develop lupus nephritis when their immune system attacks the kidneys.

If you or a loved one is living with lupus nephritis — or lupus in general — it’s important to understand who develops the condition, what it looks like, how it can impact you, and how to best manage it. Here are seven things to know about lupus nephritis.

1. Lupus Nephritis Is a Kidney Condition

Lupus is an autoimmune disease that involves the production of autoantibodies. Autoantibodies are involved with many lupus symptoms, including lupus nephritis. Antibodies are small proteins produced by the immune system to fight infection. They normally bind to foreign invaders and destroy them. In some autoimmune diseases, the immune system makes antibodies that bind to the body’s own tissues (self-tissues) and organs. When antibodies bind to self-tissues, they are called autoantibodies.

During lupus, the immune system makes many different kinds of autoantibodies that bind to self-tissues and organs and cause damage to these areas. When autoantibodies bind to self-tissues, they can accumulate in the blood and get deposited in the kidneys. Autoantibodies can also directly attack the kidney tissue.

The damage to the kidneys during lupus nephritis is due to autoantibodies getting stuck in the small blood vessels of the kidney and to autoantibodies attacking the kidney itself. The ensuing inflammation can impair the kidneys’ ability to filter excess water and waste out of the blood and into the urine so it can be removed from the body. If left untreated, lupus nephritis can lead to poor kidney function or kidney failure. Individuals with more severe lupus nephritis will usually experience kidney failure and require dialysis or a kidney transplant.

Classes of Lupus Nephritis

Lupus nephritis can be categorized into six classes, or stages. These classes are determined by the results of a kidney biopsy. A doctor will use the biopsy to look at the amount of kidney damage that has occurred.

Many of the classes of lupus nephritis are measured based on the damage to the glomeruli in the kidneys. Glomeruli are unique structures in the kidney primarily made of tiny, specialized blood vessels that filter out waste from the bloodstream. The classes of lupus nephritis are described as:

• Class 1 — There is little disease involvement of the kidney.
• Class 2 — There is some inflammation in the kidneys.
• Class 3 — Less than half of the glomeruli are involved in the nephritis.
• Class 4 — More than half of the glomeruli are involved in the nephritis.
• Class 5 — Deposits of autoantibodies are found around the glomeruli.
• Class 6 — More than 90 percent of the glomeruli are damaged.

Learn more about the classes of lupus nephritis.

2. About Half of Adults Living With Lupus Develop Lupus Nephritis

It’s fairly common for a person living with lupus to develop lupus nephritis. Around 50 percent of adults with lupus will develop lupus nephritis. Children with lupus are even more likely to have the condition: Around 80 percent of them are likely to develop lupus nephritis.

Scientists believe that gender and race or ethnicity can play a role in determining who is likely to develop lupus nephritis. Around 90 percent of the individuals living with lupus are women, according to Lupus Foundation of America. However, according to Mayo Clinic, men are more likely to have lupus nephritis. Additionally, Black, Hispanic, and Asian American people have a higher risk for developing lupus nephritis than white people, according to Mayo Clinic.

3. Lupus Nephritis Is Difficult To Prevent — but It’s Treatable

Lupus nephritis can be difficult to prevent in people with lupus. Taking medication that suppresses immune activity or the production of autoantibodies may reduce a person’s likelihood of developing lupus nephritis.

If you do develop lupus nephritis, know that most people with the condition do well over the long term — though you may need to take medications for years and get regular checkups.

4. Changes to Urine Are Among Telltale Symptoms of Lupus Nephritis

If you’re living with lupus and notice changes to the appearance of your urine, lupus nephritis may be the culprit. People with the condition have foamy urine, which is caused by proteinuria, protein in the urine. They also may have hematuria, blood in their urine.

Other signs and symptoms of lupus nephritis include:

• Edema (swelling of the hands, feet, ankles, legs, or face)
• Hypertension (high blood pressure)
• Weight gain
• Frequent urination

Read more about lupus nephritis signs and symptoms.

If you develop any of these symptoms, you should speak with your doctor as soon as possible. They have several tools at their disposal to test for lupus nephritis.

Tests for Lupus Nephritis

The condition is diagnosed using tests that analyze the blood, urine, and kidney tissue. These tests assess the kidney function, as well as any damage that may have occurred.

Urine Test

Damage to the kidneys during nephritis affects the glomeruli. These blood vessels are important for filtering out waste and excess water. They also must make sure the blood retains substances like protein. The damage to the glomeruli during lupus nephritis leads to extra protein leaking out into the urine. A doctor can order an analysis of the protein levels in someone’s urine to determine if they may have lupus nephritis.

Blood Test

Creatinine is a waste product produced by the natural breakdown of the muscles. When the kidneys are functioning properly, they will filter creatinine out of the blood and into the urine. Your doctor may order a blood test to look for excess levels of creatinine in the blood to help diagnose lupus nephritis.

Kidney Biopsy

In some cases, a kidney biopsy is needed to diagnose lupus nephritis. This entails removing a very small sample of a person’s kidney tissue. This is usually performed in a hospital or an outpatient center under light sedation or general anesthesia. Once the biopsy is completed, a pathologist — a doctor who specializes in looking at tissue under a microscope — will examine the tissue to look for damage caused by lupus nephritis.

5. There Are Treatments Available for Lupus Nephritis

There currently is no cure for lupus nephritis, but treatments can help reduce symptoms and prevent the condition from progressing. People with lupus nephritis can have a positive outlook with treatment.

Treatments for lupus nephritis often focus on suppressing the immune system and inflammation. Treatment approaches may also target the symptoms of lupus nephritis, such as swelling in the arms and legs and high blood pressure. Commonly prescribed medicines include immunosuppressants and blood pressure medications.

Read more about treatments for lupus nephritis.

6. As Many as 30% of People With Lupus Nephritis Develop Kidney Failure

Left untreated, lupus nephritis can lead to severe complications. Among them is long-term kidney damage, or chronic kidney disease (CKD). As CKD progresses and kidney function gets worse, end-stage renal disease (ESRD) — also called kidney failure — may occur. Between 10 percent and 30 percent of people with lupus nephritis will develop ESRD. People with ESRD will need to rely on kidney transplantation or dialysis. Dialysis is a medical procedure that helps remove waste from the blood.

Proliferative nephritis is the most severe form of lupus nephritis. It causes scars in the tissue of the kidneys. These scars affect kidney function, which worsens as scarring accumulates.

Individuals with lupus nephritis are also at higher risk for heart and blood vessel problems. They may also be at higher risk for some kinds of cancer, including B-cell lymphoma.

7. Dietary Changes Can Help Manage Lupus Nephritis

If you have lupus nephritis, your doctor may recommend lifestyle changes. For example, they may suggest adopting a low-sodium diet to help manage the condition. Limiting your intake of protein — such as meat and dairy products — may also help. So, too, can eating low-potassium varieties of fruits and vegetables, as too much potassium can put a strain on your kidneys if they aren’t functioning well. Low-potassium produce includes blueberries, pineapple, watermelon, cucumbers, and onions.

On the other hand, eating more foods with healthy fats — such as nuts, avocado, and salmon — can help.

Read more about what to eat and what to avoid if you have lupus nephritis.

Connect With Others Who Understand

MyLupusTeam is the social network for people with lupus and their loved ones. On MyLupusTeam, more than 218,000 members come together to ask questions, give advice, and share their stories with others who understand life with lupus. More than 14,000 members have lupus nephritis.

Are you living with lupus nephritis? Share your experience in the comments below, or start a conversation by posting on your Activities page.