Unmasking Hematuria: 20 Potential Causes of Blood in Urine Without Pain

Causes of Painless Hematuria

Hematuria is a term for blood in the urine, which can often be alarming when detected. As the name suggests, painless hematuria presents with no discomfort or pain but raises concern due to its numerous possible underlying causes. This article delves into the 10 most common causes of painless hematuria.

Red blood cells seen on light microscopy on urinary cytology, next to benign urothelial cells (pap stain).
Red blood cells were seen on light microscopy on urinary cytology next to benign urothelial cells (pap stain).

1. Urinary Tract Infections (UTIs)

Urinary tract infections occur when bacteria infiltrate the urinary system, multiplying within and leading to inflammation. Women are more commonly affected due to their shorter urethra, increasing the likelihood of bacterial migration from the skin to the bladder.

How UTIs Lead to Hematuria

When bacteria cause a UTI, the bladder and urethra’s lining can become inflamed, leading to bleeding, which is visible as blood in the urine.

2. Bladder Infections (Cystitis)

Cystitis, a specific type of UTI, is an infection localized to the bladder. It can result from bacterial invasion or can be triggered by certain drugs, radiation therapy, or the use of catheters.

Why Cystitis Causes Hematuria

The bladder’s lining can become irritated and inflamed during a bout of cystitis. This inflammation may cause the capillaries in the bladder wall to bleed, contributing to hematuria.

3. Kidney Infections

Kidney infections usually stem from a lower urinary tract infection that ascends to the kidneys. Symptoms often include fever, back pain, frequent urination, and hematuria.

The Connection Between Kidney Infections and Hematuria

Kidney infections can lead to inflammation and bleeding in the kidneys, which presents as blood in the urine.

4. Bladder or Kidney Stones

Bladder or kidney stones are hard mineral deposits that form within these organs. While small stones might not cause symptoms, larger stones can cause significant discomfort and lead to hematuria.

How Stones Cause Hematuria

Stones traveling through the urinary tract can scrape the lining, causing bleeding. Even stationary stones can cause irritation and blood in the urine.

Diagnosing and Treating Bladder or Kidney Stones

Imaging studies, including CT scans and ultrasounds, are used to diagnose stones. Treatment may involve increased fluid intake, pain relievers, or, in severe cases, surgical intervention.

5. Certain Medications

Some drugs, such as aspirin, anticoagulants (blood thinners), and certain antibiotics, can cause or exacerbate hematuria.

These medications can cause urinary tract bleeding or worsen existing bleeding, leading to hematuria.

6. Vigorous Exercise

In some cases, strenuous activities such as running or intense workouts can lead to painless hematuria. This type of hematuria is sometimes referred to as “jogger’s hematuria,” but it can happen with any vigorous activity.

How Exercise Contributes to Hematuria

The exact mechanism is not well understood. It could be due to bladder trauma, dehydration, or the breakdown of red blood cells that occurs during sustained aerobic exercise.

7. Enlarged Prostate

The prostate gland, which is only found in men, can sometimes enlarge due to a condition called benign prostatic hyperplasia (BPH). As the prostate enlarges, it can press against the urethra (the tube that urine passes through), causing a variety of urinary symptoms, including hematuria.

Why an Enlarged Prostate Causes Hematuria

The increased pressure on the urinary tract can lead to bladder irritation and, potentially, blood in the urine. In some cases, the enlarged prostate may also cause a urinary tract infection, which could lead to hematuria.

8. Kidney Disease

Various kidney diseases, including glomerulonephritis, pyelonephritis, and polycystic kidney disease, can result in hematuria. These conditions can damage the kidneys’ small filtering systems, allowing blood cells to leak into the urine.

How Kidney Diseases Lead to Hematuria

In conditions like glomerulonephritis, the kidneys’ filtering system becomes inflamed or damaged, releasing red blood cells into the urine.

9. Genetic Disorders

Certain inherited disorders can cause hematuria. For example, sickle cell anemia, an inherited disorder that affects red blood cells, and Alport syndrome, a condition that affects the filtering membranes in the glomeruli of the kidneys, can both cause blood in the urine.

The Role of Genetic Disorders in Hematuria

In conditions like sickle cell anemia, the shape of red blood cells can cause them to become trapped in the kidneys’ tiny blood vessels, leading to hematuria. In Alport syndrome, the damaged glomerular filters allow blood to seep into the urine.

10. Cancer

Though it’s not the most common cause, malignancies such as bladder, kidney, or prostate cancer can cause hematuria. Hematuria from cancer is usually painless, and often, no other symptoms are evident in the early stages of these diseases.

Why Cancer Causes Hematuria

Tumors in the bladder, kidney, or prostate may bleed into the urinary tract, causing visible blood in the urine.

11. Trauma

Physical injuries to the kidney or bladder can lead to painless hematuria. This could occur from a direct blow to the area, a fall, or an accident causing injury to the urinary system.

How Trauma Causes Hematuria

A forceful impact can rupture the small blood vessels in the kidneys or bladder, leading to the presence of blood in the urine.

12. Exposure to Certain Chemicals

Long-term or heavy exposure to certain chemicals can cause bladder irritation and subsequently hematuria. These chemicals could be those used in the dye industry or certain medications, including cyclophosphamide and ifosfamide.

The Role of Chemical Exposure in Hematuria

Prolonged exposure to these substances can irritate the bladder’s lining, leading to inflammation and potentially causing hematuria.

13. Certain Diseases and Infections

Other diseases and infections can cause hematuria besides kidney and bladder infections. For example, malaria, a parasitic infection, and schistosomiasis, caused by a parasitic worm, can lead to hematuria.

How Diseases and Infections Contribute to Hematuria

These diseases can damage the blood vessels in the urinary tract, leading to bleeding that presents as hematuria.

14. Post-Menopausal Women

Post-menopausal women are at an increased risk for painless hematuria. The lower estrogen levels following menopause can lead to thinning of the lining of the bladder and urethra, potentially causing hematuria.

Why Post-Menopause Leads to Hematuria

With reduced estrogen levels after menopause, the urinary tract lining becomes thinner and more fragile, making it more susceptible to bleeding and causing hematuria.

15. Certain Medical Procedures

Medical procedures that involve the urinary tract, such as a kidney biopsy or a urinary catheter, can cause hematuria. In most cases, this hematuria is temporary.

The Impact of Medical Procedures on Hematuria

These procedures can cause temporary trauma to the urinary tract, resulting in short-term bleeding and hematuria.

16. Anticoagulant and Antiplatelet Medications

These medications thin the blood and reduce its ability to clot. While they are vital for treating and preventing conditions like heart disease and stroke, they can occasionally lead to painless hematuria.

The Connection Between Blood Thinners and Hematuria

These drugs work by reducing the blood’s clotting ability, which can lead to increased bleeding. This bleeding can sometimes occur in the urinary tract, leading to hematuria.

17. Endometriosis in the Urinary Tract

While endometriosis typically involves the uterus, ovaries, and fallopian tubes, it can occasionally affect the urinary tract. This condition involves the type of tissue that typically lines the uterus growing outside of it, including on the bladder.

How Endometriosis Contributes to Hematuria

When endometriosis affects the bladder, it can cause irritation and inflammation, leading to hematuria.

18. Arteriovenous Malformation

An arteriovenous malformation (AVM) is a connection between the arteries and veins in your body that isn’t usually there. When these occur in the kidneys, they can lead to hematuria.

The Role of AVM in Hematuria

AVMs can lead to higher pressure and potential bleeding in the affected area. In the kidneys, this can cause blood to appear in the urine.

19. Prolonged or Intense Dehydration

Dehydration can cause dark, concentrated urine, and in severe or prolonged cases, it can lead to hematuria.

The Link Between Dehydration and Hematuria

Dehydration can concentrate the urine, irritating the bladder and potentially leading to hematuria. In extreme cases, dehydration can cause kidney damage, another potential source of hematuria.

20. Interstitial Cystitis

Also known as painful bladder syndrome, interstitial cystitis is a chronic condition characterized by bladder pressure, bladder pain, and sometimes pelvic pain. However, in some cases, it might present with hematuria in the absence of significant pain.

Why Interstitial Cystitis Causes Hematuria

Interstitial cystitis can cause inflammation and bladder wall irritation, occasionally leading to bleeding, visible as hematuria.


  1. Mayo Clinic – Hematuria
  2. Cleveland Clinic – Hematuria
  3. National Kidney Foundation – Hematuria
  4. American Kidney Fund – Hematuria
  5. MedlinePlus – Hematuria

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Disclaimer: The information provided in this article is intended for informational purposes only. It’s not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your healthcare provider with any questions or concerns you may have regarding your health.

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Tanzir Islam Britto

Hello, I'm Dr. Tanzir Islam Britto. As a dedicated physician, I've embarked on my medical journey at Bangabandhu Sheikh Mujib Medical College (BSMMC), previously known as Faridpur Medical College, where I pursued my Bachelor of Medicine and Bachelor of Surgery (MBBS). I completed my degree at Shahabuddin Medical College (SMC). Alongside my medical career, I am an amateur writer and an active social media advocate, where I share insights into health, wellness, and more.

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