Bloody Urine (Hematuria): Causes, Evaluation, and When to Seek Care

Hematuria—blood in the urine—can stem from a wide range of conditions, from benign to life-threatening. Common causes include:

Urinary Tract & Kidney

• Urinary tract infection (UTI): Especially common in women; inflammation irritates the bladder lining.
• Kidney stones: Cause abrasion and bleeding as they pass.
• Glomerulonephritis: Inflammation of the kidney's filtering units.
• Kidney disease: Various chronic conditions disrupt filtration.

Bladder & Prostate

• Cystitis / interstitial cystitis: Bladder infection or chronic inflammation.
• Benign prostatic hyperplasia (BPH) or prostatitis: In men, prostate enlargement or infection can cause bleeding.

Other Causes

• Trauma: Injury to kidneys, bladder, or urethra from accidents, sports, or procedures.
• Cancer: Bladder, kidney, or prostate cancer—though hematuria alone does not confirm malignancy.
• Menstruation: In women, vaginal bleeding can contaminate urine samples.
• Medications: Anticoagulants (blood thinners) increase bleeding risk.
• Rare disorders: Sickle cell anemia, Alport syndrome, other inherited kidney diseases.

When to see a doctor: Any visible blood in urine warrants prompt medical evaluation. Workup typically includes urinalysis, urine culture, imaging (ultrasound, CT), and possibly cystoscopy to identify the source and guide treatment.