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 bacterial infection. This usually ascends the urethra (tube that connects the bladder to the outside world through which you pass urine). The causative organism is most commonly E coli, a bacterium which lives harmlessly in the bowel. Another cause of the same symptoms is physical irritation and bruising of the urethra from sexual intercourse (this is known as 'honeymoon cystitis').

Is cystitis infectious?

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

How is cystitis treated?

Bacterial infection is effectively treated with antibiotics. Nitrofurantoin and trimethoprim are commonly used. Only small doses are needed as it is removed from the body in the urine, so it is concentrated right where it's needed. Other antibiotics, such as pivmecillinam and fosfomycin, are also options but usually used as second line treatment if nitrofurantoin or trimethoprim are ineffective or the doctor has culture results of the urine that show a different antibiotic is effective.

Start order

How is cystitis diagnosed?

Burning or stinging when passing urine, urgency and frequency are typical symptoms, and if you have had a urinary tract infection before you are likely to recognise it. Apart from listening to the description of the symptoms, if seeing a doctor face-to-face, a urinalysis test may be done. This simple test involves dipping a dipstick into your urine sample. Colour change 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.

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

Symptoms 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 performed in cases where treatment has not helped. In the meantime (it takes 2 days from when the sample is received) another antibiotic can be prescribed, such as nitrofurantoin if not used first line, pivmecillinam, 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?

Yes, alcohol does not interact with nitrofurantoin or trimethoprim antibiotics. Of course while your body is fighting an infection it is best that you do not compound unwellness by intoxication. There are certain 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, not normally the cause of urinary infections. However, they can cause cause some dental, gut, and vaginal infections.

Why do I get 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 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 low.

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 to colonise 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 which contains the friendly bacteria, Lactobacillus acidophilus, may help the yeast infection thrush. 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 vagina with soap. This increases irritation. Washing decreases amounts of both natural lubricant and 'good bacteria' that live in the vagina. This causes discomfort, accentuating the sensation of needing to pass urine and 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 your acute symptoms. 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 recurrent urinary tract infections there is some evidence that cranberry products and D-mannose may help prevent further infections.

Do men get cystitis?

Yes, but they need to see their GP. Men have much longer urethras than women and it is harder for the gut bacteria to reach the bladder. When men get cystitis, infection can be more serious, and there may be an underlying reason for infection. Urinary obstruction by urethral stricture, an enlarged or infected prostate gland or tumours needs to be ruled out.

Must I finish the antibiotics course?

Yes. Taking just part of the course can result in the bacteria not being killed off. There is 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 can I only have one course of antibiotics every 6 months?

If you are having 2 or more infections in 6 months then this would be classified as recurrent urinary tract infections. In this case it is 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. Longer courses of antibiotics are sometimes used in these situations.

Start order

Dr Tony Steele

Authored 18 February 2010 by Dr Tony Steele
MB ChB Sheffield University 1983. Former hospital doctor and GP.

Reviewed by Dr C. Pugh, Dr B. Babor, Dr A. Wood, Dr P. Hunt
Last reviewed 30 June 2021
Last updated 15 October 2021