Ever get a whiff of chicken broth or something fishy or fruity — but you’re in the bathroom, not the kitchen? Among MyLupusTeam members, these and other seemingly unusual urine smells are a common topic.

Your kidneys work hard to filter out unneeded water and waste from your bloodstream, turning it into urine. Normally odorless, your urine can change color and smell depending on the concentrations of waste, sugar, and other substances in your blood. If you’re living with a kidney disease such as lupus nephritis, you may notice changes in your urine.

“So about a week ago, I went to the restroom and realized my urine smelled like cat urine,” one member said. “This has never happened before. I thought maybe I was a bit dehydrated. Can anyone shed some light?”

In this article, we’ll discuss the different urine smells that members have mentioned and explain the possible causes. If you detect any changes in your urine color or odor, talk to your doctor or nephrologist (a doctor who specializes in treating kidney diseases).

Lupus and Your Kidneys

According to the National Institute of Diabetes and Digestive and Kidney Diseases, nearly half of adults with lupus have renal (kidney) disease. Lupus nephritis is caused by antibodies (immune system proteins) that attack your kidneys, resulting in inflammation and damage. Your kidneys can’t function properly, filter waste, or regulate your hormone levels and blood pressure as well as before.

Your kidneys contain millions of tiny blood vessels that act as filtration units. To maintain your blood’s chemical balance, they remove water, waste, and salts that are then excreted as urine. Your urine is made of:

• Water
• Urea (waste made from breaking down proteins)
• Salts such as chloride, potassium, magnesium, calcium, and phosphate
• Ammonium
• Creatinine (waste made by muscle cells)

Your urine odor may change based on what you eat and drink, how well your kidneys function, and what you excrete. Certain waste products, glucose (your body’s preferred form of sugar), and other substances can all affect urine’s smell.

Here are four urine odors you may notice while living with lupus nephritis. Some may be related to your disease, while others may be due to diet and taking certain medications.

1. Chicken Broth or Chicken Soup

Many MyLupusTeam members have noticed their urine smells similar to chicken broth or chicken soup. One posted, “Urine smells like chicken broth: Sorry for the question, but this is new. Anyone else have this happen before?”

The question resonated with a number of members, prompting replies such as these:

• “I’m so glad you asked this question. As I moved into more lupus symptoms, I noticed my urine smelled like chicken soup, sort of. It’s protein in your urine, which means your kidneys are not working as well as they should.”
• “I dealt with the same thing. My urine always has very high protein levels.”
• “The smell could be high proteins or just even what you’re eating. You can go to the pharmacy and buy a basic urine test to see if anything is off.”

High protein levels in urine, also known as proteinuria, are common in people with kidney disease and lupus nephritis. Normally, glomeruli — tiny blood vessels in your kidneys — filter water and salts out of your blood but prevent larger particles like blood cells and proteins from passing through.

In lupus nephritis, your glomeruli are damaged by inflammation, allowing proteins into your urine. In addition to smelling like chicken broth, your urine may be foamy or frothy. Other symptoms of lupus nephritis include edema (swollen legs, face, and hands), blood in your urine, and weight gain. If you notice any combination of these symptoms, it’s best to make an appointment with your health care provider.

2. Ammonia

If your urine smells like cat pee or ammonia, it may be time to talk to your doctor or nephrologist. MyLupusTeam members have discussed this urine odor and the symptoms that accompany it.

“Strong ammonia smell in urine,” one member wrote. “Before getting prescribed Plaquenil, I often had sharp pains in my lower back and flank area accompanying flares. I also have had consistently small levels of protein in my urine, and recently they found red blood cells in my urine.”

A member responded, “I have protein and blood in my urine — had the flank pain also. They did a kidney biopsy and found I had lupus and stage 3B kidney disease. I’d ask your doctor to check your kidneys better.”

“I’m having the same issue — it’s embarrassing in public, it’s that bad. If I go to a public restroom my pee smells horrible,” another replied.

Reasons your urine may smell like ammonia include:

• Lupus nephritis — Damaged kidneys can’t properly filter your blood, so they make less urine with a higher ammonium concentration.
• Dehydration — With less water in your body, your urine is more concentrated and contains higher levels of ammonium.
• Urinary tract infection (UTI) — A bacterial infection in your bladder, kidneys, or urethra can make your urine smell like ammonia.
• Kidney stones — These solid masses consist of ammonium and other excreted salts that can make your urine smell different.

If you’re experiencing abdominal pain or flank pain and peeing less than normal, plus your urine smells like ammonia, it’s best to make an appointment with your doctor.

3. Fruity or Sweet-Smelling Odor

Does your urine smell fruity or sweet? It may be a sign of uncontrolled type 2 diabetes. Studies show that between 5 percent and 15 percent of people with systemic lupus erythematosus (SLE) have diabetes.

SLE interferes with your cells’ ability to use glucose for energy. As a result, your blood sugar levels increase, and your kidneys get rid of the excess sugar in your urine. If you’re living with SLE and notice that your urine smells sweet, it may be a sign that your blood sugar levels are too high. Your doctor can perform blood work to check your blood sugar and diagnose diabetes.

Fruity-smelling urine is a telltale sign of diabetic ketoacidosis, a life-threatening condition that requires immediate treatment. In diabetic ketoacidosis, your body can’t use glucose for energy, so it breaks down fat in your liver for fuel. This process creates ketones that are excreted in your urine, making it smell fruity.

If your urine smells fruity and you’re experiencing any of the following symptoms, seek medical attention immediately:

• Extreme thirst
• Urinating much more often than normal
• Fatigue
• Abdominal pain
• Headache
• Fruity-smelling breath
• Dry mouth and skin

4. Fishy or Foul-Smelling Odor

Certain foods and medications can also affect how your urine smells. For example, asparagus, onions, and garlic contain asparagusic acid, which is broken down into sulfur compounds. You may notice your urine smells like sulfur or rotten eggs after eating those foods. A recent seafood meal can lead to a fishy or foul-smelling odor.

Some antibiotics, immunosuppressants (medications that calm an overactive immune system), diabetes drugs, and vitamins also contain sulfur-related compounds that give urine a particular scent. Your urine may smell different if you’re taking supplements or drugs such as the following:

• Vitamin B6, a water-soluble vitamin excreted in urine
• Sulfa antibiotics, such as sulfamethoxazole/trimethoprim (Bactrim) to treat UTIs
• Immunosuppressants, such as sulfasalazine (Azulfidine) to treat rheumatoid arthritis
• Sulfonylureas, such as glimepiride (Amaryl) and glipizide (Glucotrol) to treat diabetes

Talk to Your Doctor About Urine Smells

Your urine says a lot about your health — if your urine smells unusual or if you have new lupus or lupus nephritis symptoms, your doctor can help. Your rheumatologist and nephrologist will work together to determine what tests need to be done, such as checking your kidney function and looking for any abnormalities.

These tests include:

• Urinalysis — Identifies pathogens causing UTIs, blood cells, and waste and salt concentration
• Kidney biopsy — Involves studying a small piece of your kidney tissue under a microscope to look for inflammation and damage in lupus nephritis
• Dipstick test — Checks for proteinuria

Once you receive your test results, your doctor will discuss the next steps and form a treatment plan. When living with lupus, it’s important to take care of your kidney health to prevent other health problems.

Talk With Others Who Understand

MyLupusTeam is the social network for people with lupus and their loved ones. On MyLupusTeam, more than 221,000 members come together to ask questions, give advice, and share their stories with others who understand life with lupus.

Have you noticed any changes in your urine’s smell? Did you ask your doctor what the odor might mean? Share your experience in the comments below, or start a conversation by posting on your Activities page.