Skip to content

25 Warning Signs Your Kidneys Send You

From back pain to bloody noses, kidney issues can manifest in some seriously surprising ways.

Your kidneys play an essential role when it comes to keeping you healthy, filtering waste products out of your body and promoting the growth of healthy red blood cells. Unfortunately, despite how important healthy kidneys are to your overall well-being, the signs of kidney problems are often so subtle that many people don't realize there's an issue with these vital organs until it's too late. If you want to stay healthy, read on to discover the symptoms of kidney problems you can't afford to ignore. And for more ways to safeguard your health, make sure you know the 20 Most Commonly Overlooked Cancer Symptoms, According to Doctors.

Pain under your ribs

Rib pain surprising cancer symptom

While many associate kidney problems with lower back pain, it's actually pain near your rib cage that's more likely to indicate a kidney problem. "Your kidneys are actually higher than you think and anatomically positioned beneath your ribs," explains Jennifer Linehan, MD, urologist and associate professor of urologic oncology at the John Wayne Cancer Institute at Providence Saint John's Health Center in Santa Monica, California.

Side pain

Woman at the office with a pain in her side

Kidney stones, which are hard deposits of salt and minerals that form inside the kidney, can be extremely painful when they pass through the ureter and bladder. The Mayo Clinic says that you'll know the pain you're experiencing is from kidney stones when it's in your side and comes in waves. If your pain is caused by kidney stones in particular, "the pain can be very severe and usually changing position does help or hurt," says Linehan. And for more pains to pay attention to, check out 25 Common Pains You Should Never Ignore.


Man suffering from stomach ache nauseous

When a kidney stone moves from your kidney to your ureter, it can block the passing of urine. When this happens, you may experience "swelling and pain, which can be accompanied by nausea and vomiting," says S. Adam Ramin, MD, a urologic surgeon and medical director of Urology Cancer Specialists in Los Angeles.

Blood in your urine

Close-up of steel toilet handle

If you notice blood in your urine or you notice it looks even a little bit red or brown, it's important that you get to a doctor before any potential problems get worse. "Blood in your urine may indicate kidney stones, a tumor, a kidney or bladder infection, or irritation anywhere in the urinary system," explains Leann Poston, MD, of Invigor Medical. And for more signals of serious health issues, check out 30 Warning Signs Your Heart Is Trying to Send You.

A metallic taste in your mouth

Woman sticking out her tongue in disgust

When your kidneys stop adequately filtering toxins from your blood, waste products often show up in unexpected places, including some surprising symptoms north of the neck. In fact, "if these wastes build up in the blood, it may… make food taste like metal," explains Poston.

Bad breath

Shot of a handsome young man smelling his breath during his morning grooming routine

Similarly, Jennifer Schau, DDS, notes on her website that when your kidneys are unable to filter out the excess urea in your bloodstream, you may notice a "foul odor" being emitted from your mouth—in other words, you have bad breath. And for more about your oral hygiene, check out 23 Things You're Doing That Would Horrify Your Dentist.

Gum disease

man in pain holding his gum.

A metallic taste and bad breath aren't the only ways in which kidney disease can manifest in your mouth. According to Schau, kidney issues can also cause gum disease, "leading to the decay and loss of teeth." A 2013 meta-analysis published in the Pakistan Journal of Medical Sciences found that patients with chronic kidney disease are far more likely to have periodontal disease, as well as other issues like overgrown gums and dry mouth, than those without serious kidney problems.

Swollen hands and feet

Woman with swollen ankle foot

Since the kidneys are responsible for filtering excess water from the body, when they aren't performing this function properly, that excess fluid can redistribute, particularly in your extremities.

"Swelling of your legs, ankles, and feet may be a sign that the kidney is not removing excess fluids or sodium from the body," says Poston. "When the kidneys leak too much protein into the urine, swelling may result."

Loss of appetite

man feeling full not hungry

If your favorite foods have suddenly lost all appeal, that could be a sign of serious kidney problems. While Ramin says that early stage kidney cancer has few symptoms, when the disease is more advanced, "kidney cancer may cause sensation of fullness in the abdomen [and] loss of appetite." And if you're noticing you can't keep weight on, check out 11 Subtle Signs Your Rapid Weight Loss Is Something Serious.


Bathroom door open looking at a toilet

According to oncologist Przemyslaw Twardowski, MD, kidney cancer can also cause "disturbances in body chemistry"—namely, an overabundance of calcium in the bloodstream, which can lead to constipation. If you're experiencing this issue and think it's a sign of a bigger problem, talk to your primary care provider about having your calcium levels checked.



That high fever you've been battling may be more than just a symptom of a cold or flu coming on. "Infection of the kidneys usually cause flank pain and fevers," says Ramin. He says that someone with a kidney infection will usually see their temperature rise and fall instead of staying constant. Want to protect your liver, too? Discover these 20 Warning Signs of Liver Damage to Never Ignore.


Senior man looking at a calendar confused

You might not associate your kidney function and your cognitive function, but if the former starts to decline, it may cause serious changes in your mental state. "Patients who develop sudden onset of kidney failure will have fluid retention and build up toxins in their blood such as urea nitrogen," explains Ramin. He says that sudden kidney failure can cause both "mental fogginess or confusion," so if tests have ruled out a neurological issue, ask your doctor for an assessment of your kidney health, too.


iron deficiency blood test

Your recent anemia diagnosis may not just be a sign that you could use some more iron-rich foods in your diet. Ramin says that in rare cases, it can be the result of kidney problems. "If blood testing shows anemia and/or if the urine is visibly clear, but under microscopic exam, blood is found in the urine, then a CT Scan is the best test to confirm presence of renal fracture," Ramin explains.


woman fainting in the park, heart warning signs

Feeling suddenly unsteady on your feet? It could be your kidneys telling you to get to the doctor. "Dizziness and loss of concentration can result from anemia brought on by kidney failure," according to Dr. Lam Coaching, a team of licensed physicians specializing in adrenal fatigue syndrome. They explain that anemia reduces the amount of blood and oxygen going to your brain, causing that woozy feeling.

High blood pressure

Doctor checking patient's blood pressure

Those off-the-charts blood pressure readings might be a sign that your kidneys aren't functioning at optimal levels. "Even though a person with kidney disease may have no symptoms and only discover their condition through bloodwork, there are some symptoms that definitely point to this condition," including difficulty controlling high blood pressure, according to Dr. Lam Coaching.


Older man bored retired

While the early stages of kidney disease may present with few symptoms, "fatigue is an often-experienced symptom of kidney disease, especially in the later stages," write the experts at Dr. Lam Coaching.

This is often the result of lower red blood cell production associated with kidney health issues, which leads to inadequate blood and oxygen supply throughout the body. "A reduced amount of oxygen to the cells leads to feelings of fatigue," according to Dr. Lam Coaching.

Itchy skin

man scratching arm

That dry, itchy skin isn't necessarily a sign you need to be more diligent about your moisturizing routine. "When kidneys fail, there is a build-up of waste in your blood, called uremia, that is known to cause your skin to become very itchy," explains Alain Michon, MD, medical director at Ottawa Skin Clinic. In fact, a 2015 paper published in Seminars in Nephrology notes that up to 40 percent of patients with end-stage kidney disease develop pruritus, or chronic itching.

High blood sugar

Man with Diabetes Testing His Blood Sugar Misdiagnosed Men's Health Issues

According to the National Kidney Foundation, diabetes is the leading cause of kidney failure, accounting for 44 percent of new cases. Due to the toll diabetes takes on the kidneys as a result of the damage it does to the body's red blood cells, diabetics are also at risk of developing diabetic kidney disease, a condition that further reduces kidney function.

Chronic nosebleeds


Granulomatosis with polyangiitis (GPA) is a disease characterized by swelling of the blood vessels in the kidneys, nose, sinuses, throat, or lungs. According to the American Kidney Fund, the first sign of this condition is usually a runny nose or frequent nosebleeds. Though GPA doesn't always affect the kidneys, any case that does can lead to chronic kidney disease or even kidney failure, so it's important to speak to a doctor if nosebleeds become a regular occurrence.

Frequent urination

an empty roll of toilet paper against a blue background, annoying things people do

If you find yourself heading to the restroom with increased frequency, it could be a sign that something is up with your kidneys. "If the kidney filters are damaged, it can cause an urge to urinate, especially at night," says Renee Matthews, MD. Considering that frequent urination is also associated with health issues like diabetes and urinary tract infections, this symptom definitely merits a trip to the doctor.

Foamy urine

White hand flushing a toilet in the bathroom

Often when kidney function is impaired, your "urine has bubbles that won't go away when you flush the toilet," says Matthews. "This foam is similar to the foam you see when scrambling eggs because the protein found in urine is albumin, which is the same protein that is found in eggs."

Swelling around your eyes

Woman with swelling around the eyes

According to the Mayo Clinic, kidney disease can create "extra fluid and sodium in your circulation," which often leads to swelling around the eyes. In the case of nephrotic syndrome, in which too much protein is secreted through the urine, swelling also occurs due to lower levels of albumin in the blood.

Inability to eat meat and dairy

young white woman refusing glass of milk
Shutterstock/Africa Studio

Interestingly enough, advanced kidney disease can make protein-rich foods like meat and dairy taste absolutely terrible. According to the Kidney & Urology Foundation of America, that's because these foods break down into nitrogen and creatinine, waste products that unhealthy kidneys are unable to filter out of the bloodstream.

Unintentional weight loss

Black woman stepping on a scale to weigh herself

Weight loss isn't always a good thing, especially if it's unintentional. If you're shedding pounds for no reason, it may be because your kidneys aren't functioning properly. After monitoring nearly 4,000 patients with chronic kidney disease (CKD) for nearly six years, researchers behind a 2018 study published in the Official Journal of the National Kidney Foundation found that "significant weight loss [begins] relatively early during the course of CKD."

Shortness of breath

man short of breath

When your kidneys aren't properly filtering and excreting waste products and fluid, the Urology Care Foundation notes that shortness of breath can occur, particularly if fluid has built up in your lungs.

Filed Under