Your kidneys work quietly around the clock, filtering waste and excess fluid from your blood, helping control blood pressure, balancing minerals, and supporting healthy red blood cell production.
One of the challenges with kidney disease is that early kidney damage may cause few or no noticeable symptoms. Symptoms can become more apparent as kidney function declines.
The following 23 signs are worth knowing. They do not automatically mean you have kidney disease, because many can have other causes. Persistent or unexplained symptoms should be discussed with a healthcare professional.
1. Changes in How Often You Urinate
A noticeable change in urination frequency can sometimes occur with kidney or urinary problems.
You may find yourself urinating much more often, particularly at night, or notice a significant change from your normal pattern.
However, frequent urination can also result from diabetes, urinary infections, medications, caffeine, or drinking large amounts of fluid.
2. Urinating More at Night
Waking repeatedly during the night to urinate is called nocturia.
It can occur for many reasons, but persistent nocturia may sometimes be associated with reduced kidney function.
It is also common with aging, prostate problems, diabetes, heart conditions, and certain medications.
3. Foamy or Frothy Urine
Occasionally seeing bubbles in the toilet is usually not a concern.
However, urine that repeatedly appears unusually foamy or frothy may indicate protein in the urine, known as proteinuria.
Persistent protein in the urine can be an important sign of kidney damage and should be evaluated.
4. Blood in the Urine
Pink, red, or cola-colored urine may indicate blood in the urinary tract.
Blood in urine can have numerous causes, including urinary infections, kidney stones, medications, prostate conditions, and kidney disease.
It should not simply be assumed to be a kidney problem, but unexplained blood in the urine deserves medical evaluation.
5. Swelling in the Legs or Ankles
Damaged kidneys may have difficulty removing excess sodium and fluid from the body.
This can contribute to swelling, particularly around the feet, ankles, and lower legs.
Swelling can also be caused by heart, liver, vein, or medication-related problems.
6. Swelling Around the Eyes
Puffiness around the eyes, especially when it is persistent or most noticeable in the morning, can sometimes be associated with protein leaking into the urine.
There are many other causes of facial or eye swelling, so this symptom alone cannot diagnose kidney disease.
7. Unexplained Fatigue
Kidney disease can cause fatigue for several reasons.
Reduced kidney function may contribute to anemia, accumulation of waste products, sleep problems, and other changes that leave a person feeling unusually tired.
Persistent fatigue is common and has many possible causes, including thyroid problems, anemia, poor sleep, infections, and nutritional deficiencies.
8. Weakness
As kidney function declines, changes in fluid and mineral levels can contribute to weakness.
Severe weakness, particularly when it develops suddenly, requires prompt medical assessment because it can have many serious causes.
9. Nausea
Waste products can build up in the bloodstream when kidney function becomes significantly impaired.
This may contribute to nausea, loss of appetite, or a general feeling of illness.
Nausea is much more commonly caused by gastrointestinal infections, medications, pregnancy, migraines, and other conditions, so it should not be interpreted as proof of kidney disease.
10. Loss of Appetite
A reduced appetite can occur when kidney disease becomes advanced.
Changes in taste, nausea, and accumulation of waste products may contribute.
However, persistent loss of appetite can occur with many medical conditions and should be investigated if it continues without an obvious explanation.
11. Metallic Taste in the Mouth
Some people with advanced kidney disease report an unusual or metallic taste.
Changes in taste can also result from medications, infections, dental problems, and other conditions.
A persistent unexplained change in taste is worth mentioning to a healthcare professional.
12. Unpleasant Breath
Advanced kidney failure can sometimes cause breath to have an unusual ammonia-like or urine-like odor because waste products accumulate in the blood.
This is generally associated with significant kidney dysfunction rather than ordinary mild kidney problems.
Bad breath is much more commonly related to dental or oral conditions.
13. Dry or Itchy Skin
Kidney disease can cause persistent itching, particularly in advanced stages.
Changes in mineral and phosphorus balance and accumulation of certain substances in the blood may contribute.
Dry skin, allergies, eczema, medications, and many other conditions can also cause itching.
14. Muscle Cramps
Kidney problems can contribute to abnormalities in minerals and electrolytes, potentially causing muscle cramps or discomfort.
Cramps can also result from dehydration, exercise, medications, pregnancy, or other electrolyte disturbances.
Frequent or severe cramps should be discussed with a healthcare professional.
15. Muscle Twitches
Significant disturbances in electrolytes associated with advanced kidney disease may cause muscle twitching or other neuromuscular symptoms.
Sudden or severe twitching, weakness, or confusion requires medical assessment.
16. Trouble Sleeping
People with chronic kidney disease may experience difficulty sleeping.
Sleep problems can be related to itching, restless legs, discomfort, sleep apnea, anxiety, or other complications.
Poor sleep by itself does not indicate kidney disease.
17. Difficulty Concentrating
When kidney disease becomes advanced, the accumulation of waste products and other metabolic changes may affect mental clarity.
A person may experience difficulty concentrating or feel unusually mentally tired.
Sudden confusion, however, should be treated as an urgent medical symptom.
18. Headaches
Headaches can occur alongside many health conditions, including high blood pressure.
Because kidney disease and high blood pressure are closely connected, recurring headaches should not automatically be attributed to kidney problems.
Severe or sudden headaches require urgent assessment, particularly when accompanied by neurological symptoms.
19. Shortness of Breath
Advanced kidney disease can contribute to shortness of breath through fluid accumulation or anemia.
However, breathing difficulty can also be caused by heart and lung conditions, infections, blood clots, and other serious problems.
Sudden or severe shortness of breath requires emergency medical attention.
20. High Blood Pressure
The kidneys play an important role in regulating blood pressure.
Kidney disease can contribute to high blood pressure, while uncontrolled high blood pressure can also damage the kidneys.
This creates a potentially harmful cycle.
Regular blood-pressure checks are particularly important for people at increased risk of kidney disease.
21. Changes in Urine Color
Urine can naturally change color depending on hydration, food, supplements, and medications.
Very dark urine may occur with dehydration, while red or brown urine can sometimes indicate blood or other abnormalities.
Persistent unusual urine color should be discussed with a healthcare professional.
22. Pain in the Side or Back
Pain in the area beneath the ribs or toward the side of the back can occur with certain kidney problems, including kidney stones or kidney infections.
But ordinary back pain is extremely common and is usually related to muscles or the spine.
Severe side or back pain accompanied by fever, vomiting, blood in the urine, or difficulty urinating requires prompt medical attention.
23. Changes in Fluid Balance
Some people with significant kidney dysfunction may experience noticeable changes in how much fluid their body retains or eliminates.
This can appear as swelling, rapid changes in body weight, or significant changes in urine output.
Sudden major changes should be medically evaluated.
Who Is More at Risk for Kidney Disease?
Certain conditions and factors increase the risk of chronic kidney disease, including:
- Diabetes
- High blood pressure
- Heart disease
- Family history of kidney disease
- Older age
- Previous kidney injury
- Certain autoimmune conditions
- Some inherited kidney disorders
- Long-term use of certain medications
Having a risk factor does not mean that kidney disease is inevitable.
How Is Kidney Disease Detected?
Symptoms alone are not a reliable way to determine whether your kidneys are functioning properly.
Simple medical tests can provide much more useful information.
Common evaluations include:
Blood Test
A blood test can measure creatinine, which is used to estimate kidney filtration, commonly reported as the estimated glomerular filtration rate (eGFR).
Urine Testing
A urine test can detect abnormalities such as blood or protein.
A urine albumin-to-creatinine ratio (UACR) is commonly used to look for albumin leakage, which can be an early marker of kidney damage.
Blood Pressure Measurement
Checking blood pressure is important because high blood pressure can both contribute to and result from kidney disease.
When Should You Contact a Doctor?
Make an appointment with a healthcare professional if you have persistent or unexplained:
- Foamy urine
- Blood in your urine
- Swelling of your feet, ankles, or face
- Significant changes in urination
- Persistent fatigue
- Unexplained nausea or appetite loss
- High blood pressure
- Recurrent side or back pain
If you have diabetes, high blood pressure, or another kidney-disease risk factor, ask your healthcare professional whether regular kidney-function testing is appropriate.
When to Seek Urgent Care
Some symptoms require prompt or emergency medical attention.
Seek urgent medical care for symptoms such as:
- Severe difficulty breathing
- Sudden confusion or loss of consciousness
- Very little or no urine production
- Severe swelling that develops rapidly
- Severe flank pain accompanied by fever or vomiting
- Significant blood in the urine
- Severe weakness or symptoms suggesting a serious electrolyte disturbance
The Bottom Line
Your kidneys can lose function without producing obvious symptoms, particularly during the early stages of chronic kidney disease.
The 23 signs above can occur with kidney problems, but none of them alone proves that your kidneys are failing. Many have much more common explanations.
If you notice persistent changes in urination, swelling, unexplained fatigue, foamy urine, blood in the urine, or other concerning symptoms, don’t try to diagnose yourself from symptoms alone. A healthcare professional can evaluate you with blood pressure measurements, blood tests, and urine testing.
Medical Disclaimer
This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. If you are experiencing concerning or worsening symptoms, consult a qualified healthcare professional. For severe breathing difficulty, sudden confusion, loss of consciousness, or other medical emergencies, seek emergency care immediately.