What causes cystitis?

Cystitis is the inflammation (-itis) of the bladder (cyst) wall. It is also called a lower urinary tract infection (UTI) or water infection. A majority of the time the cause is a bacterial infection. This usually usually reaches the bladder from outside up the tube from where you pee (urethra). The most common bacteria causing cystitis is E.coli, which usually lives in the bowel causing no problems there. In a woman, it is not far for it to travel to the urethra and then into the bladder.

Sometimes only the urethra is inflamed (urethritis) but the symptoms can feel very similar to cystitis.

For further information see NHS - cystitis.

What are the symptoms of cystitis?

  • Stinging, burning, or pain when peeing (dysuria).
  • A need to pee more often, or very soon after previous time (frequency).
  • Unable to hold pee for long (urgency).
  • Dark, cloudy, or smelly pee sometimes with blood in it.
  • Discomfort low down in the tummy.
  • Feeling slightly unwell, achey, sick, and tired.

If infection spreads to the kidneys then there will also be back pain below the ribs, a fever and much more severe illness. This requires more than simple cystitis treatment and you should contact your own GP, or out-of-hours service.

What is 'honeymoon' cystitis?

This describes cystitis triggered by sex, which can irritate and bruise the female urethra, making it more vulnerable to allowing infection to reach the bladder.

What is urethritis?

Urethritis is a sore, inflamed urethra (tube leading from bladder to outside, through which you pee). It can, like cystitis, lead to stinging and pain when peeing. Urethritis can sometimes (especially in men) be caused by other types of infection particularly STIs such as chlamydia or gonorrhoea.

Is cystitis infectious?

No. It is an infection, but cannot be transmitted to others.

How is cystitis treated?

Sometimes cystitis will go away by itself in a few days. If symptoms are mild, self-treatment and 'wait-and-see' for a few days may be the best approach. An antibiotic will often shorten the length of symptoms.

If symptoms are severe or worsening, antibiotics are usually required. Nitrofurantoin and trimethoprim are commonly used. Only small doses and short three day courses are needed as the antibiotic is removed from the body in the urine, so it is concentrated right where it's needed. Other antibiotics, such as pivmecillinam, fosfomycin, or cefalexin, are also options but are usually used as second line treatment if nitrofurantoin or trimethoprim haven't worked or when the doctor has urine test culture results that show a different antibiotic will be more effective.

Cystitis treatment

How is cystitis diagnosed?

If you have had a urinary tract infection before you are likely to recognise it. The classic symptoms of cystitis are dysuria, frequency, and urgency. If you have the classic symptoms no further tests may be needed. Sometimes a urinalysis test may be done. This simple test involves dipping a dipstick into your urine sample. Colour changes on the stick indicates the presence of various substances which confirm infection.

Can I do urinalysis myself at home?

If in doubt you can leave a sample with your GP, but yes, they are available to buy. The specific substances to look out for, as they confirm infection are nitrites (produced by bacteria and an indication they are present), leukocyte esterase (this is released from white blood cells/immune cells showing they are active, i.e. fighting bacteria) and less specifically, blood and protein, which can be present in cystitis but also in other situations. Nitrites and leukocytes are more likely to be positive in urine which has been held in the bladder for at least 4 hours.

How soon after I start antibiotic treatment will I feel better?

Symptoms should start to resolve after just 1 day of treatment, sometimes even after a few hours. After the burning sensation and urgency to pass urine have settled, you can be left with a few days of irritation, the sensation of needing to pass urine.

How can I treat the pain?

You can buy painkillers, such as paracetamol or ibuprofen from the chemist to reduce discomfort.

What if I don't feel any better?

Nitrofurantoin or trimethoprim are effective in most cases, and are therefore usually prescribed straight away, without sending urine off to identify which bacteria are present. However, if it is going to work, it will do so quickly. If your symptoms do not improve after 48 hours, it is worth speaking with your doctor to review the situation. The bacteria which are causing your infection could be resistant to nitrofurantoin or trimethoprim. Sending a urine sample to the local lab for microscope examination and culture will establish whether there is a bacterial cause, and if so which antibiotics will be effective. This test is usually performed in cases where treatment has not helped. In the meantime, as results can take 1-3 days from when the sample is received, another antibiotic can be prescribed, such as nitrofurantoin if not used first line, pivmecillinam, cefalexin, or fosfomycin.

Will antibiotics stop my contraceptive pill from working?

No, previously it was advised that antibiotics interfere with the pill. Now it is understood that the only antibiotics that decrease the function of the pill are rifampicin and rifabutin (used to treat tuberculosis and meningitis).

Can I drink alcohol if I'm on antibiotics for cystitis?

Yes, usually. Alcohol does not interact with nitrofurantoin or trimethoprim antibiotics. Of course while your body is fighting an infection drinking alcohol may make you feel more unwell. There are certain other antibiotics, namely metronidazole or tinidazole, which when taken with alcohol can result in an unpleasant reaction with abdominal pain, vomiting, flushing, and headaches. These medications are used against anaerobic bacteria or micro-organisms called protozoa, which are not normally the cause of urinary infections. However, they can cause some dental, gut, and vaginal infections.

Why do I get vaginal thrush when I take antibiotics?

Thrush is caused by candida albicans, a yeast that is often harmlessly present in the vagina. When you take an antibiotic, not only does it kill the bacteria it was prescribed for, but it can destroy 'good' bacteria too. If the balance of bacteria in the gut is altered, this commonly causes diarrhoea and abdominal cramps. If the bacteria in the vagina are reduced in number, yeasts which are not affected, can then multiply and result in thrush.

How do I treat vaginal thrush?

The discomfort and itching together with thick white discharge caused by yeast infection is treatable. Medical treatment for vaginal infections caused by candida include vaginal pessaries and creams containing antifungal medications: Canesten (clotrimazole) or Gyno-Daktarin (miconazole) or oral antifungal medications for example Diflucan (fluconazole). Other options are probiotics - there is more evidence for direct application rather than taking by mouth. If you are diabetic you are less likely to get thrush if your blood sugars remain controlled.

What are probiotics?

Probiotics are products that contain living organisms such as bacteria or yeasts which are used to improve health. They can be eaten or applied directly to body areas in order to restore a normal balance of microbes. They may be a food or a supplement, or applied as a cream. When eaten, good bacteria may help the gut. When applied to the vagina, yoghurt containing the friendly bacteria, Lactobacillus acidophilus, may help to cure the thrush infection. There is evidence to support the role of probiotics, but there are also studies which don't show effectiveness. The jury is still out on this one.

I feel so dirty having an infection, does washing help?

No, please don't be tempted to wash the vulva and vagina with soap. This increases irritation. Washing decreases amounts of both natural lubricant and 'good bacteria' that live in the genital area. This can increase discomfort and the sensation of needing to pass urine so prolonging or worsening cystitis symptoms.

What is the role of cranberry juice?

There is currently no evidence to support taking cranberry products or cystitis sachets to improve symptoms of cystitis. It helps to drink plenty of water (2-3 litres or 4-5 pints a day), which helps to flush the bacteria out of the bladder. However if you have frequent repeated urinary tract infections there is some evidence that cranberry products and D-mannose may help prevent further infections.

Do men get cystitis?

Yes - men must consult their GP, as infection may be more serious. Men have much longer urethras than women and it is harder for the gut bacteria to reach the bladder. So when men get cystitis there may be another underlying reason for infection. Urinary obstruction by urethral stricture or stones, an enlarged or infected prostate gland, or tumours need to be ruled out.

Must I finish the antibiotics course?

Yes. Taking just part of the course can result in the bacteria not being properly killed off. There is then a risk the bacteria may develop resistance. Resistant bacteria (strains of bacteria which do not respond to antibiotics) can be difficult to treat and can be a cause for serious concern.

Why does Dr Fox limit how often I can have a course of antibiotics for cystitis?

There are two reasons:

  1. If you are having 2 or more infections in 6 months then this would be classified as recurrent urinary tract infections. It is important to discuss recurrent cystitis with your own doctor, to see if there is another reason behind the repeat infections, possibly relating to the menopause, sex, or even diabetes. In this case it may be recommended that urine is sent for urinalysis by your doctor to check what bacteria are causing the infections and what antibiotics they are sensitive to, to ensure you are receiving the correct treatment.
  2. To limit development of antibiotic resistance. Repeated use of any antibiotic may encourage antibiotic resistant infections. This is more likely to be an issue with trimethoprim and so it is not recommended to take another course of trimethoprim within 3 months of a previous course. Nitrofurantoin is usually recommended instead.

Do cystitis antibiotics contain lactose?

Yes, unfortunately both trimethoprim tablets and nitrofurantoin capsules all contain lactose.

Cystitis treatment

Dr Tony Steele

Authored 18 February 2010 by Dr Tony Steele
MB ChB Sheffield University 1983. Former hospital doctor and GP. GMC no. 2825328

Reviewed by Dr C. Pugh, Dr B. Babor, Dr A. Wood
Last reviewed 14 March 2023
Last updated 19 January 2024