What Causes Cystitis

Cystitis is when your bladder is inflamed. A urinary tract infection (UTI) is the most common cause of cystitis.  When you have one, bacteria in your bladder cause it to swell and get irritated, which leads to symptoms like the urge to pee more often than normal. Possible causes of cystitis include:

  • urinary tract infection (UTI)
  • taking certain drugs
  • exposure to radiation
  • ongoing use of a catheter
  • irritating hygiene products
  • complications of other health conditions
  • Interstitial cystitis

Urinary tract infection (UTI): UTIs typically occur when bacteria outside the body enter the urinary tract through the urethra and begin to multiply. Most cases of cystitis are caused by a type of Escherichia coli (E. coli) bacteria. But other types of bacteria can cause infections, too. These may include:

  • Proteus mirabilis
  • Klebsiella pneumoniae
  • Staphylococcus saprophyticus
  • Group B streptococci
  • Lactobacillus
  • S. saprophyticus
  • enterococci

Bacterial bladder infections may happen in women after sex. Even in those who aren’t sexually active, UTIs can happen because the female genital area often harbors bacteria that can cause cystitis.

Noninfectious factors also may cause the bladder to become inflamed:

Drug-related cystitis. Some medicines, such as certain drugs used to treat cancer (chemotherapy), can cause inflammation of the bladder as the broken-down components of the drugs exit the body.

Radiation cystitis. Radiation treatment of the pelvic area can cause inflammatory changes in bladder tissue.

Foreign-body cystitis. Long-term use of a catheter can make bacterial infections and tissue damage more likely. Both of these can cause bladder inflammation.

Chemical cystitis. Some people may be extra sensitive to chemicals found in certain products. These might include bubble bath, personal hygiene spray or spermicidal jelly. An allergic-type reaction can happen within the bladder, causing inflammation.

Cystitis associated with other conditions. Cystitis may sometimes occur as a complication of other conditions, such as diabetes, kidney stones, an enlarged prostate or spinal cord injury.

Interstitial cystitis. The cause of this chronic bladder inflammation, also called painful bladder syndrome, is not clear. Most cases happen in women. The condition can be difficult to diagnose and treat.

Risk factors

Some people are more likely than others to develop bladder infections or repeated urinary tract infections. Women can have this problem. A key reason is physical anatomy. Women have a short urethra. This means bacteria that can cause an infection don’t have as far to travel to reach the bladder.

You may be at greater risk of bladder infections or repeated UTIs if you:

  • Are sexually active. During sex, bacteria can be pushed into the urethra.
  • Use certain types of birth control. Using a diaphragm increases the risk of a UTI. Diaphragms that contain spermicide may increase risk even more.
  • Are pregnant. Hormone changes during pregnancy may increase the risk of a bladder infection.
  • Have gone through menopause. Changes to hormones that happen after menopause often can lead to UTIs.

Other risk factors include:

  • Interference with the flow of urine. This can occur in conditions such as a stone in the bladder or an enlarged prostate.
  • Changes in the immune system. This can happen with certain conditions, such as diabetes, HIV infection and cancer treatment.
  • Long-term use of urinary catheters. These tubes may be needed in people with chronic illnesses or in older adults. Prolonged use can put you at greater risk of bacterial infections as well as bladder tissue damage.