Urinary tract infection in women: symptoms and treatment

A common infection, usually harmless

Cystitis is an infection of the bladder, often caused by bacteria from the gut such as E. coli. It mainly affects women, because their urethra (the small tube that carries urine out of the body) is short. It is unpleasant but usually not dangerous, and can clear up on its own within about a week. Antibiotics usually make the symptoms go away faster.

Typical symptoms of simple cystitis

Symptoms often start suddenly:

• burning or pain when passing urine;
• needing to pass urine often and urgently, in small amounts;
• a feeling that the bladder is not completely empty, discomfort in the lower belly;
• cloudy urine, sometimes a little blood in the urine.

Simple cystitis does not cause fever. Unusual vaginal discharge or itching points rather to another cause, such as a yeast infection or a sexually transmitted infection.

Cystitis or kidney infection: telling them apart

Sometimes the infection travels up from the bladder to the kidney: this is a kidney infection (pyelonephritis). It is more serious and is treated with antibiotics without delay. Contact a doctor the same day if you have, with or without burning when passing urine:

• fever or chills;
• pain in the lower back or in your side, below the ribs (loin pain);
• a feeling of being really ill (general malaise).

Outside opening hours, call the on-call GP service on 1733 (see our emergencies page). A high fever with great weakness, a very fast heartbeat, fast breathing or confusion can signal a serious infection (sepsis): call 112.

When should you always see a doctor?

Simple cystitis means cystitis in a healthy adult woman who is not pregnant. In the following situations, do not treat yourself; book an appointment with your general practitioner:

• you are pregnant or think you might be;
• the symptoms concern a man or a child;
• you have diabetes, a weakened immune system, a disease or abnormality of the kidneys or urinary tract, or you have had a kidney infection before;
• you have a urinary catheter;
• you are a frail older person: the infection may then show up as fever, unusual tiredness or confusion;
• cystitis keeps coming back (3 times or more a year);
• symptoms last more than a few days, get worse or do not improve despite treatment;
• blood remains visible in the urine after recovery, or you have difficulty passing urine.

How is it diagnosed?

The diagnosis is based first on your symptoms. The doctor may dip a test strip (dipstick) into a urine sample. It looks for nitrites, which some bacteria produce, and for white blood cells, a sign of inflammation.

A urine culture, done in the laboratory, identifies the bacterium and the antibiotics that work against it. For simple cystitis, it is usually not needed. It is useful during pregnancy, in men and children, in case of diabetes, a weakened immune system, an abnormality of the urinary tract or a previous kidney infection, for recurrent cystitis or when treatment fails, and for a kidney infection, before starting the antibiotic.

Without symptoms, a “check-up” urine test is useless: bacteria in the urine without symptoms (asymptomatic bacteriuria) are not treated, except during pregnancy.

Treating simple cystitis according to the Belgian guide

The Belgian guide to anti-infective treatment in outpatient practice (BAPCOC), revised in 2026, offers several options, to be chosen with your doctor:

• Waiting while relieving symptoms: for a healthy woman who is not pregnant and has never had a kidney infection, this is an option. A painkiller such as paracetamol can help. If the infection lasts more than a week, an antibiotic is prescribed.
• A delayed prescription: you only start the antibiotic if your symptoms have not improved after a few days.
• An antibiotic straight away: the first choice is nitrofurantoin, 100 mg three times a day for 5 days, preferably with meals. The second choice is fosfomycin, a single 3 g dose, preferably at bedtime; it cures the infection slightly less often.

During pregnancy, treatment lasts 7 days and is adjusted to the culture result; nitrofurantoin is avoided after week 36. Symptoms may continue for a few days after the end of treatment: this does not necessarily mean it has failed.

Why avoid self-medicating with antibiotics?

Avoid taking leftover antibiotics, someone else's antibiotics or antibiotics bought without a prescription, for example abroad:

• it may not be the right medicine, dose or duration;
• every unnecessary use encourages resistant bacteria, against which antibiotics no longer work;
• broad-spectrum antibiotics, such as fluoroquinolones (for example ciprofloxacin), should be kept in reserve for more serious infections such as kidney infections; since 2019, the European Medicines Agency has restricted their use because of rare but sometimes long-lasting side effects (tendons, muscles, nerves).

What helps, and what lacks solid evidence

The Belgian guide recommends:

• drinking plenty, up to 3 litres a day, unless your doctor advises otherwise (for example in heart failure); in one study, women who drank little had almost half as many recurrences when they drank an extra 1.5 litres of water a day;
• emptying the bladder completely, without putting off passing urine;
• passing urine after sex;
• talking to your doctor if you use condoms or a diaphragm with spermicide.

Cranberry: a 2023 Cochrane review concludes that cranberry products probably reduce the risk of a new urinary tract infection in women who get them often (about a quarter less risk), and in children. No clear benefit was shown in older people living in care homes, during pregnancy or when the bladder does not empty properly. The ideal dose is unknown, and cranberry does not treat cystitis that has already started. Ask for advice if you have kidney disease or take a blood thinner (such as warfarin).

No solid evidence: D-mannose did not reduce recurrences in a large trial in general practice in 2024. Bearberry (uva-ursi), a plant, is offered without any scientific basis.

Preventing recurrences

From 3 episodes of cystitis a year, a urine culture helps identify the bacterium. For a healthy woman who is not pregnant, several options can be discussed with your doctor:

• a cranberry extract for prevention (not advised in older people);
• after the menopause, vaginal oestrogens (cream or pessaries), to be reviewed at least once a year;
• self-treatment: you keep a prescribed antibiotic at home and start it at the first symptoms you clearly recognise, following a plan drawn up together, for 6 to 12 months at most;
• a low dose of antibiotic after sex or every evening, to be stopped after 6 to 12 months.

When to ask for quick advice

Contact us the same day if you have fever, chills, loin pain or feel unwell, urinary symptoms during pregnancy, or cannot pass urine, or if your condition does not improve after 48 hours of treatment. At Maison Médicale Parc Astrid in Anderlecht, we see patients in French, Dutch, English and Turkish. Do you live in Brussels and are not yet registered? See our new patient page.

Sources

• BCFI/CBIP – New BAPCOC guide 2026: urogenital infections (2026)
• BCFI/CBIP – Repertory 11.5, BAPCOC guide: acute cystitis (2026)
• NHG – NHG-Standaard Urineweginfecties (2025)
• Cochrane – Cranberries for preventing urinary tract infections (2023)
• Hooton et al. – Increased daily water intake and recurrent cystitis, JAMA Intern Med (2018)
• Hayward et al. – D-mannose for prevention of recurrent UTI, JAMA Intern Med (2024)
• EMA – Fluoroquinolones: restrictions on use (2019)