Cystitis (sis-TYE-tis) is inflammation of the bladder, also known as a bladder infection. It's the most common type of urinary tract infection (UTI) and mostly affects children and adult women. More to Know Cystitis is usually caused by bacteria (typically E. coli) that enter the body through the urethra and spread to the bladder. If not treated, the infection can travel to the kidneys and become a more serious problem. Cystitis can occur in people who are otherwise healthy and have no medical problems. Irritants such as bubble baths or feminine hygiene products, poor toilet or hygiene habits, an abnormality in the structure or function of the urinary tract, drug interactions, or long-term catheter use all can cause a bladder infection. Symptoms of cystitis include a persistent urge to urinate (pee), a burning sensation when urinating, cloudy or strong-smelling urine, low-grade fever, and a feeling of pressure or pain in the lower abdomen. Wetting accidents in toilet-trained children often indicate cystitis. For infants and young children, cystitis may be harder to detect because symptoms are less specific. Sometimes fever is the only sign. Keep in Mind Bladder infections are painful and inconvenient, but most are caused by bacteria and can easily be treated with antibiotics. If you have blood in your urine, pain with urination, back or side pain, fever, nausea or vomiting, or abdominal pain, see your doctor immediately as these are signs of a possible infection in the urinary tract. All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts. Back to Articles Related Articles Urinary Tract Infections A urinary tract infection (UTI) is one of the most common reasons that teens visit a doctor. Learn about the symptoms of UTIs, how they're treated, and more in this article. Read More First Aid: Pain With Urinating (Peeing) When it hurts to pee, a urinary tract infection (UTI) is usually to blame. But there are other causes. Here's what to do. Read More Your Urinary System You pee every day, but what makes it happen? Find out in this article for kids about the urinary system. Read More Why Am I Getting Urinary Tract Infections? Find out what the experts have to say! Read More Kidneys and Urinary Tract The kidneys perform several functions that are essential to health, the most important of which are to filter blood and produce urine. Read More Urinary Tract Infections (UTIs) Urinary tract infections (UTIs) are common in kids. They're easy to treat and usually clear up in a week or so. Read More Bedwetting Bedwetting is an issue that millions of families face every night. Most of the time it's not a sign of any deeper medical or emotional issues and kids eventually grow out of it. Read More Urine Test: Automated Dipstick Urinalysis Automated dipstick urinalysis results may point to a urinary tract infection (UTI) or injury, kidney disease, or diabetes. Read More Kidneys and Urinary Tract The bean-shaped kidneys, each about the size of a child's fist, are essential to our health. Their most important role is to filter blood and produce urine. Read More Urine Test: Routine Culture A urine culture is used to diagnose a urinary tract infection (UTI) and determine what kinds of germs are causing it. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.