Causes for blood in the urine include urinary tract infections, kidney infections, bladder or kidney stones, kidney disease or cancer, according to Mayo Clinic. In men, it may also suggest prostate problems.
A urinary tract infection is a common reason for blood in the urine, and this condition occurs when bacteria enters into the body via the urethra, explains Mayo Clinic. In addition to blood in the urine, a urinary tract infection may cause the urge to urinate, pain when urinating or urine with a strong smell. A kidney infection is another cause of blood in the urine, and in this case, occurs when bacteria enters the kidneys. The signs include pain and frequent urination, but also fever and pain in the flank.
Bladder or kidney stones may also cause blood in the urine, and in this case, the formation of these crystals occurs naturally, states Mayo Clinic. These stones are usually painless, but as a stone tries to pass, it can be very painful, and blood may appear in the urine. Kidney disease can also cause blood in the urine and usually has triggers such as infections, immune conditions or blood vessel diseases. Cancer may also cause blood in the urine, though it usually does not occur until the later stages. The most common cancers that cause this are bladder, kidney or prostate cancer.