Risk factors

Almost anyone — including children and teens — can have red blood cells in the urine. Factors that make this more likely include:

• Age. Many men older than 50 have occasional hematuria due to an enlarged prostate gland.
• A recent infection. Kidney inflammation after a viral or bacterial infection (post-infectious glomerulonephritis) is one of the leading causes of visible urinary blood in children.
• Family history. You might be more prone to urinary bleeding if you have a family history of kidney disease or kidney stones.
• Certain medications. Aspirin, nonsteroidal anti-inflammatory pain relievers and antibiotics such as penicillin are known to increase the risk of urinary bleeding.
• Strenuous exercise. Long-distance runners are especially prone to exercise-induced urinary bleeding. In fact, the condition is sometimes called jogger's hematuria. But anyone who works out strenuously can develop symptoms.