Cystitis is one of the most common conditions affecting the urinary tract and a frequent reason for visits to GPs, emergency departments and urology clinics. Although many people use the terms 'cystitis', bladder infection and urinary tract infection (UTI) interchangeably, they do not always mean the same thing. Understanding the difference is important because some episodes of cystitis are caused by nonbacterial factors, and some patients with urinary symptoms do not require antibiotics.
Most cases of cystitis are caused by a bacterial infection of the bladder, usually due to Escherichia coli (E. coli), which normally lives harmlessly in the bowel before entering the urinary tract. However, bladder inflammation can also occur without infection. Conditions such as bladder pain syndrome (interstitial cystitis), pelvic radiotherapy, certain medications and even prolonged ketamine use can all inflame the bladder and produce symptoms that closely resemble a urinary tract infection.
Cystitis is extremely common, particularly in women. More than 50% of women will experience at least one urinary tract infection during their lifetime, and almost 25% will go on to develop recurrent infections. Each episode can cause pain, frequent trips to the toilet, disturbed sleep, time away from work and considerable anxiety, particularly when infections keep returning.
The reassuring news is that most episodes of uncomplicated bacterial cystitis respond well to treatment, while recurrent or more complex cases can often be successfully investigated and managed once the underlying cause has been identified.
This article explains what cystitis is, how it differs from a urinary tract infection, the symptoms to look out for, the different causes of bladder inflammation, how cystitis is diagnosed and treated, when further investigation is needed and how recurrent episodes can often be prevented.
What is cystitis?
Cystitis simply means inflammation of the bladder. The word comes from the Greek kystis, meaning bladder, and the suffix -itis, meaning inflammation.
The most important point to understand is that cystitis describes inflammation, not a specific disease.
In everyday medical practice, cystitis most commonly refers to acute bacterial cystitis, where bacteria infect the bladder and trigger inflammation of its inner lining. In approximately 70–95% of uncomplicated infections, the responsible organism is Escherichia coli (E. coli).
However, bacteria are not the only cause of cystitis. The bladder can become inflamed for several different reasons, including:
- Bacterial infection, the commonest cause.
- Bladder pain syndrome (interstitial cystitis), where inflammation occurs without bacterial infection.
- Radiation cystitis, following radiotherapy to the pelvis.
- Drug-induced cystitis, caused by medications such as cyclophosphamide or, more rarely, cancer immunotherapy.
- Chemical cystitis, resulting from irritation by chemicals or some personal hygiene products.
- Ketamine-associated cystitis, caused by prolonged recreational ketamine use.
- Rare conditions such as emphysematous cystitis, a severe infection caused by gas-forming bacteria, usually in people with diabetes.
Although these conditions have different causes, they often produce similar symptoms because they all inflame the bladder wall. As the bladder lining becomes irritated, it becomes more sensitive, leading to pain, burning when passing urine, urinary urgency and the need to empty the bladder more frequently.
Understanding why the bladder is inflamed is the key to choosing the correct treatment. Antibiotics are highly effective for bacterial cystitis but will not improve symptoms caused by non-infectious forms of bladder inflammation.
Is cystitis the same as a urinary tract infection (UTI)?
Not exactly. Although the terms are often used interchangeably, cystitis and urinary tract infection (UTI) are not always the same thing.
A urinary tract infection (UTI) is an infection that can affect any part of the urinary tract, including:
- the kidneys;
- the ureters (the tubes connecting the kidneys to the bladder);
- the bladder; or
- the urethra (the tube that carries urine out of the body).
Cystitis specifically refers to inflammation of the bladder.
In most cases, this inflammation is caused by a bacterial infection, making acute bacterial cystitis the commonest type of lower urinary tract infection. However, the bladder can also become inflamed without bacteria being present. This is why not every episode of cystitis is technically a urinary tract infection.
Understanding this distinction helps explain why some people continue to experience urinary symptoms despite repeatedly negative urine cultures.
What is the difference between cystitis and a bladder infection?
A bladder infection is simply another name for acute bacterial cystitis.
When bacteria enter the bladder, multiply within the urine and trigger inflammation of the bladder lining, the terms 'bladder infection', 'bacterial cystitis' and bladder UTI all describe the same condition.
Patients commonly experience:
- burning or stinging when passing urine;
- needing to pass urine more frequently;
- a sudden urge to urinate;
- discomfort or pressure in the lower abdomen;
- cloudy or unpleasant-smelling urine; and
- occasionally, blood in the urine.
These symptoms develop because bacteria trigger inflammation within the bladder wall, making the bladder more sensitive and reducing the amount of urine it can comfortably hold.
Can you have cystitis without a urinary tract infection?
Yes.
Although bacterial infection is by far the commonest cause, bladder inflammation can occur without bacteria.
Examples include:
- bladder pain syndrome (interstitial cystitis);
- radiation cystitis after pelvic radiotherapy;
- inflammation caused by certain medications;
- chemical irritation from substances entering the bladder; and
- ketamine-associated cystitis.
These conditions often produce symptoms that closely resemble a bacterial bladder infection, including urinary frequency, urgency and pelvic pain. However, because bacteria are not responsible, antibiotics usually provide little or no benefit.
This is one reason why urine culture is so important in patients with persistent or recurrent urinary symptoms.
Can a bladder infection spread to the kidneys?
Yes, although this is uncommon when bacterial cystitis is recognised and treated appropriately.
If bacteria travel from the bladder up the ureters into the kidneys, they can cause pyelonephritis, a kidney infection. This is a more serious form of urinary tract infection that usually causes:
- fever;
- chills or shivering;
- pain in the back or side below the ribs (loin pain);
- nausea or vomiting; and
- feeling generally unwell.
Unlike uncomplicated cystitis, kidney infections often require prompt antibiotic treatment and occasionally admission to hospital, particularly if there are signs of sepsis, a serious reaction to infection affecting the whole body.
Fortunately, most episodes of uncomplicated bacterial cystitis remain confined to the bladder and do not progress to kidney infection.
Why is understanding the difference important?
Knowing whether symptoms are caused by bacterial cystitis, another form of bladder inflammation or a more serious urinary tract infection helps determine the most appropriate treatment.
For example:
- Acute bacterial cystitis may require antibiotics, depending on the severity of symptoms and the individual patient.
- Bladder pain syndrome requires an entirely different treatment approach because no bacterial infection is present.
- Kidney infections usually require more urgent treatment than uncomplicated bladder infections.
- Recurrent urinary symptoms with negative urine cultures should prompt consideration of other bladder conditions rather than repeated antibiotic prescriptions.
Understanding the difference between cystitis and a urinary tract infection therefore helps ensure that patients receive the correct diagnosis and avoid unnecessary or ineffective treatment.
What are the symptoms of cystitis?
The symptoms of cystitis usually develop suddenly, often over a few hours, although they can occasionally appear more gradually.
Most symptoms occur because inflammation makes the bladder lining more sensitive. As a result, the bladder begins sending signals that it needs emptying even when it contains only a small amount of urine. At the same time, inflamed tissues become irritated as urine passes over them, leading to discomfort and burning.
Although symptoms vary between individuals, the most common features of acute bacterial cystitis include:
- burning or stinging when passing urine (dysuria);
- needing to pass urine more often than usual (frequency);
- a sudden, difficult-to-control urge to pass urine (urgency);
- passing only small amounts of urine each time;
- pain, pressure or discomfort in the lower abdomen above the pubic bone;
- cloudy or unpleasant-smelling urine;
- blood in the urine (haematuria); and
- generally feeling uncomfortable or unwell without the high fever that is more typical of a kidney infection.
The severity of symptoms does not always reflect the severity of the infection. Some people develop intense discomfort from a relatively mild infection, while others experience surprisingly few symptoms.
What are the early symptoms of cystitis?
The earliest symptom is often a burning sensation when passing urine. Many people also notice that they need to visit the toilet more frequently than usual, even though only a small amount of urine is passed.
As inflammation increases, the bladder becomes more sensitive and less able to stretch comfortably. This explains why patients often feel that they need to urinate urgently despite having very little urine in the bladder.
Some people initially mistake these symptoms for dehydration or irritation before the full picture of cystitis develops over the following hours.
Why does cystitis cause burning when passing urine?
Burning occurs because inflammation damages the surface of the bladder and urethra, exposing sensitive nerve endings.
As urine passes across these inflamed tissues, it temporarily irritates the exposed nerves, producing the characteristic burning or stinging sensation known as dysuria.
This discomfort usually improves as the infection settles and the bladder lining heals.
Why do I keep needing the toilet?
This is one of the commonest symptoms of cystitis.
The bladder normally expands as it fills with urine before sending signals to the brain that it is time to empty.
During cystitis, inflammation makes the bladder wall much more sensitive. Even small amounts of urine can trigger the urge to urinate, making patients feel that they need the toilet repeatedly despite passing only a small volume each time.
This explains why urinary frequency and urgency almost always occur together.
Can cystitis cause blood in the urine?
Yes.
Inflammation can make the tiny blood vessels within the bladder lining more fragile. Small amounts of bleeding may therefore occur, causing the urine to appear pink, red or occasionally brown.
This is called haematuria, which simply means blood in the urine.
Although blood in the urine can occur with bacterial cystitis, it is important to remember that it is not specific to infection. Bladder stones, kidney stones, enlarged prostate, kidney disease and bladder cancer can all cause haematuria.
For this reason, visible blood in the urine should never automatically be assumed to be caused by cystitis, particularly if it persists after the infection has been treated or occurs without other symptoms of infection.
Can cystitis cause lower abdominal pain?
Yes.
Many patients describe discomfort, pressure or aching in the lower abdomen immediately above the pubic bone.
This occurs because the inflamed bladder wall becomes tender. As the bladder fills, it stretches the inflamed tissues, producing pain or pressure that often improves after passing urine before gradually returning as the bladder fills again.
Can cystitis cause back pain?
Not usually.
Pain confined to the lower back or side, particularly just below the ribs, is more suggestive of a kidney infection (pyelonephritis) or, in some cases, a kidney stone than uncomplicated bacterial cystitis.
Back pain occurring together with fever, chills, nausea or vomiting should be taken seriously because it may indicate that the infection has spread beyond the bladder.
Can cystitis cause fever?
Simple bacterial cystitis usually causes little or no fever.
A temperature above 38°C, shaking chills, severe illness or pain in the side of the back are more concerning for a kidney infection or another more serious condition.
These symptoms require prompt medical assessment because kidney infections are treated differently from uncomplicated cystitis and carry a greater risk of complications if left untreated.
Can cystitis cause confusion in older adults?
Older adults may sometimes develop confusion, reduced mobility or general deterioration during an infection, particularly if they are frail or have underlying medical conditions.
However, it is important not to assume that confusion alone is caused by a urinary tract infection.
Current guidance emphasises that older people should not receive antibiotics solely because bacteria are found in the urine or because they are confused. Other common causes, such as dehydration, constipation, medication side effects or other infections, should also be considered.
This distinction is important because unnecessary antibiotic treatment contributes to antimicrobial resistance and may expose patients to avoidable side effects.
What causes cystitis?
The cause of cystitis depends on why the bladder has become inflamed.
Although most people associate cystitis with a bacterial infection, there are several different causes of bladder inflammation. Identifying the underlying cause is important because each type of cystitis is treated differently. Antibiotics are effective for bacterial cystitis but have little or no role in most non-infectious forms of bladder inflammation.
Bacterial cystitis
Bacterial cystitis is by far the most common cause of cystitis and accounts for the vast majority of cases seen in primary care.
In approximately 70–95% of uncomplicated infections, the bacteria responsible are Escherichia coli (E. coli). These bacteria normally live harmlessly in the bowel, where they play an important role in digestion. Problems arise when they spread from the bowel to the skin around the anus and then enter the urethra. Once inside the bladder, they multiply rapidly, attach to the bladder lining and trigger inflammation.
Other bacteria that can cause cystitis include:
- Klebsiella pneumoniae
- Proteus mirabilis
- Enterococcus faecalis
- Staphylococcus saprophyticus, particularly in younger women
- Pseudomonas aeruginosa, more commonly in patients with urinary catheters, previous urinary tract surgery or recurrent healthcare-associated infections
Most infections occur because bacteria travel upwards through the urethra, which is why women are affected much more often than men. The female urethra is shorter and closer to the anus, making it easier for bacteria to reach the bladder.
Once bacteria reach the bladder, they use specialised hair-like structures called fimbriae to attach firmly to the bladder lining. This attachment helps them resist being flushed away during urination and allows them to multiply, producing inflammation and the typical symptoms of cystitis.
Recent research has also shown that some bacteria can invade the cells lining the bladder and form intracellular bacterial communities. These microscopic collections of bacteria may remain hidden within the bladder lining even after symptoms improve, helping to explain why some people experience recurrent urinary tract infections despite appropriate antibiotic treatment.
Why do bacteria keep coming back?
One of the most frustrating aspects of cystitis is that it often returns.
Several factors may contribute to recurrent infections, including:
- bacteria surviving within the bladder lining;
- changes in the normal bacteria living within the bowel and urinary tract (the urinary microbiome);
- menopause and reduced oestrogen levels;
- incomplete bladder emptying;
- bladder stones;
- urinary catheters;
- diabetes;
- sexual intercourse; and
- increasing antibiotic resistance.
In many patients, recurrent cystitis is not caused by one single factor but by a combination of several contributing problems.
Interstitial cystitis (bladder pain syndrome)
Bladder pain syndrome (interstitial cystitis) is a long-term condition that causes bladder pain, urinary urgency and urinary frequency without a bacterial infection.
Unlike bacterial cystitis, urine cultures are usually negative, and antibiotics are generally ineffective.
Although the exact cause remains uncertain, researchers believe that changes in the bladder lining, abnormal nerve signalling, inflammation and changes within the immune system all contribute to the condition.
Because bladder pain syndrome requires a completely different approach to diagnosis and treatment, it should not be confused with recurrent bacterial cystitis.
Radiation cystitis
Radiation cystitis may develop months or even years after radiotherapy to the pelvis for conditions such as prostate, bladder, cervical or rectal cancer.
Radiotherapy can damage the small blood vessels and lining of the bladder, leading to inflammation, urinary frequency, urgency and blood in the urine.
The severity varies considerably. Some patients experience only mild symptoms, while others develop persistent bleeding requiring specialist treatment.
Drug-induced and chemical cystitis
Some medications can directly irritate the bladder.
The best-known example is cyclophosphamide, a chemotherapy drug that can produce significant bladder inflammation if protective measures are not used.
More recently, rare cases of cystitis have also been reported following immune checkpoint inhibitors, a type of cancer immunotherapy that stimulates the immune system to attack cancer cells. In these patients, the immune system can occasionally attack healthy bladder tissue, producing symptoms that resemble bacterial cystitis despite the absence of infection.
Chemical irritation can also occur following exposure to certain products, although this is much less common than bacterial infection.
Ketamine-associated cystitis
Long-term recreational ketamine use can cause severe inflammation of the bladder.
Patients often develop:
- severe urinary frequency;
- intense urgency;
- bladder pain;
- blood in the urine; and
- progressive reduction in bladder capacity.
Unlike bacterial cystitis, this condition is caused by the toxic effects of ketamine and its breakdown products on the bladder lining. Continued ketamine use can result in permanent bladder damage, making early recognition particularly important.
Rare forms of cystitis
Several uncommon forms of cystitis are recognised.
One example is emphysematous cystitis, a rare but potentially serious infection caused by gas-forming bacteria. It occurs most commonly in people with diabetes, weakened immune systems or long-term urinary catheters. Imaging shows gas within the bladder wall or bladder cavity, and prompt treatment is required.
Other rare causes include fungal infections, tuberculosis affecting the urinary tract and parasitic infections such as schistosomiasis, which remains an important cause of bladder disease in parts of Africa and the Middle East.
Although these conditions are uncommon in the United Kingdom, they may be considered in patients with unusual symptoms, relevant travel history or persistent urinary problems that do not respond to standard treatment.
Can more than one cause be present?
Yes.
Some patients have more than one contributing factor. For example, a postmenopausal woman with diabetes may develop recurrent bacterial cystitis because reduced oestrogen changes the normal protective bacteria around the vagina, while diabetes increases the risk of infection.
Similarly, a man with an enlarged prostate may repeatedly develop bladder infections because incomplete bladder emptying allows bacteria to remain within residual urine after passing urine.
This is why identifying the underlying cause is just as important as treating the infection itself. Successfully managing cystitis often means correcting the factor that allowed the infection to develop in the first place rather than repeatedly prescribing antibiotics alone.
Why is cystitis more common in women?
Women are significantly more likely than men to develop cystitis. In fact, more than half of all women will experience at least one urinary tract infection during their lifetime, and almost one in four will develop recurrent infections.
This increased risk is largely explained by differences in female anatomy, hormonal changes and certain life events that make it easier for bacteria to reach and multiply within the bladder.
Why does female anatomy increase the risk?
The female urethra—the tube that carries urine from the bladder to the outside of the body—is much shorter than the male urethra, measuring approximately 4 cm compared with 18–20 cm in men.
This shorter distance means bacteria have a much easier journey from the skin around the genital area into the bladder.
In addition, the female urethral opening lies close to both the vagina and the anus. Because the bowel naturally contains large numbers of bacteria, particularly Escherichia coli (E. coli), bacteria can occasionally spread to the urethra and then travel into the bladder. This is known as an ascending infection, which is the most common route by which bacterial cystitis develops.
Fortunately, the body has several natural defence mechanisms that normally prevent this from happening, including regular bladder emptying, the bladder's protective lining and beneficial bacteria that help maintain a healthy environment around the urinary tract.
Does sexual activity increase the risk?
Yes.
Sexual intercourse can temporarily move bacteria towards the urethral opening, increasing the chance that they enter the bladder.
This is one reason why some women notice that symptoms develop within 24 to 48 hours after intercourse.
This does not mean that cystitis is a sexually transmitted infection (STI). Instead, sexual activity simply creates an opportunity for bacteria that are already present around the genital area to enter the urinary tract.
Women who experience repeated infections related to intercourse may benefit from specific preventive strategies, which are discussed in detail in my article on recurrent urinary tract infections.
Why does the menopause increase the risk of cystitis?
The risk of cystitis increases after the menopause because oestrogen levels fall.
Oestrogen helps maintain the health of the tissues around the vagina and lower urinary tract. It also supports the growth of beneficial Lactobacillus bacteria, which help keep the vaginal environment acidic and discourage the growth of harmful bacteria.
After the menopause:
- the tissues become thinner and more fragile;
- the number of protective Lactobacillus bacteria falls;
- the vaginal environment becomes less acidic; and
- bacteria such as E. coli find it easier to colonise the area around the urethra.
These changes increase the likelihood of bacteria entering the bladder and contribute to the higher rate of recurrent urinary tract infections seen in postmenopausal women.
This is one reason why vaginal oestrogen is recommended by both NICE and the European Association of Urology (EAU) for appropriately selected postmenopausal women with recurrent urinary tract infections.
Does pregnancy increase the risk?
Yes.
During pregnancy, hormonal changes relax the muscles of the urinary tract, causing urine to flow more slowly from the kidneys to the bladder. As the uterus enlarges, it can also partially compress the ureters and reduce complete bladder emptying.
Urine that remains within the urinary tract for longer provides bacteria with more opportunity to multiply.
For this reason, pregnant women are routinely screened for bacteria in the urine, even if they have no symptoms, because untreated infection can increase the risk of kidney infection (pyelonephritis) and pregnancy complications.
Can lifestyle factors increase the risk?
Some lifestyle and medical factors can also increase the likelihood of developing cystitis.
These include:
- inadequate fluid intake;
- delaying passing urine for long periods;
- diabetes;
- urinary incontinence;
- obesity;
- constipation;
- urinary catheters;
- previous urinary tract surgery; and
- recurrent antibiotic use that alters the normal bacterial balance.
Many of these factors are modifiable, meaning that identifying and addressing them may reduce the risk of future infections.
Can cystitis be prevented?
Not every episode of cystitis can be prevented, but understanding the factors that increase risk allows many women to reduce the frequency of future infections.
Preventive measures may include:
- maintaining adequate hydration;
- avoiding unnecessary antibiotic use;
- managing constipation;
- treating incomplete bladder emptying where present;
- using vaginal oestrogen after the menopause when appropriate; and
- considering evidence-based non-antibiotic preventive treatments in patients with recurrent infections.
I discuss these preventive treatments, including methenamine hippurate, hyaluronic acid bladder instillations and other non-antibiotic strategies, in dedicated articles within the recurrent urinary tract infection section of this website.
Can men develop cystitis?
Yes. Although cystitis is much less common in men than in women, it can occur at any age.
The lower risk is mainly due to male anatomy. The male urethra is approximately 18–20 cm long, compared with about 4 cm in women. This much longer distance makes it more difficult for bacteria to travel from the outside of the body into the bladder.
In addition, antibacterial substances produced by the prostate gland may help reduce bacterial growth within the urinary tract in younger men.
For these reasons, a healthy younger man rarely develops bacterial cystitis.
Why do men develop cystitis?
When cystitis occurs in men, there is often an underlying factor that allows bacteria to reach the bladder or prevents the bladder from emptying completely.
Common causes include:
- an enlarged prostate (benign prostatic enlargement) causing incomplete bladder emptying;
- chronic bacterial prostatitis, where bacteria persist within the prostate and repeatedly infect the urinary tract;
- urethral stricture disease, where narrowing of the urethra obstructs urine flow;
- bladder stones;
- long-term urinary catheters;
- previous urinary tract surgery;
- neurological conditions affecting bladder emptying;
- diabetes;
- weakened immunity; and
- urinary tract abnormalities.
Identifying and treating these underlying problems is often more important than simply prescribing repeated courses of antibiotics.
Are urinary symptoms in men always caused by cystitis?
No.
Many urinary symptoms commonly associated with cystitis can also occur in other urological conditions.
For example:
- an enlarged prostate commonly causes urinary frequency, urgency, a weak urinary stream and getting up at night to pass urine;
- chronic prostatitis may cause burning when passing urine, pelvic pain and urinary discomfort;
- bladder stones can produce pain, urinary frequency and blood in the urine;
- bladder cancer may present with visible blood in the urine, sometimes without pain or infection; and
- overactive bladder can cause urgency and frequency without any infection.
This is why urine testing is important before assuming that urinary symptoms are caused by bacterial cystitis.
Do men with cystitis always need further investigation?
Not always, but men are investigated more often than women because bacterial cystitis is relatively uncommon.
The need for investigation depends on several factors, including:
- whether this is the first infection or a recurrent problem;
- the severity of symptoms;
- age;
- the presence of blood in the urine;
- difficulty emptying the bladder;
- previous urinary tract surgery;
- kidney function;
- and whether the infection responds as expected to treatment.
Many men undergo further assessment to identify any underlying factor that may have contributed to the infection.
What investigations might be recommended?
Depending on the clinical situation, investigations may include:
- a urine culture to identify the bacteria causing the infection;
- measurement of the amount of urine left in the bladder after passing urine (post-void residual);
- ultrasound of the kidneys and bladder;
- flexible cystoscopy, where a small camera is passed into the bladder to examine its lining;
- CT scanning if stones or another structural abnormality are suspected; and
- blood tests to assess kidney function and signs of infection where appropriate.
These investigations are not performed routinely for every man with cystitis. Instead, they are selected according to the individual's symptoms, examination findings and medical history.
Can an enlarged prostate increase the risk of cystitis?
Yes.
An enlarged prostate is one of the commonest reasons older men develop recurrent urinary tract infections.
As the prostate enlarges, it can obstruct the flow of urine through the urethra. This may prevent the bladder from emptying completely, leaving residual urine behind after urination.
Residual urine provides bacteria with an opportunity to multiply, increasing the likelihood of recurrent bladder infections.
For some men, treating the enlarged prostate can significantly reduce the frequency of recurrent cystitis by improving bladder emptying.
Should recurrent cystitis in men be ignored?
No.
Although a single uncomplicated infection may occasionally occur, recurrent urinary tract infections in men should not simply be accepted as normal.
Repeated infections may be the first sign of an underlying problem, such as an enlarged prostate, chronic bacterial prostatitis, bladder stones, urinary obstruction, or, more rarely, bladder cancer.
Identifying and treating the underlying cause often provides a more effective long-term solution than repeated courses of antibiotics alone.
For this reason, men who develop recurrent bacterial cystitis usually require a more detailed assessment than women with uncomplicated bladder infections.
How is cystitis diagnosed?
For most people, cystitis can be diagnosed from a combination of your symptoms, medical history and a simple urine test. However, not everyone needs the same investigations. The tests recommended depend on factors such as your age, sex, pregnancy status, the severity of symptoms and whether this is your first infection or part of a pattern of recurrent urinary tract infections.
The main aim is to confirm whether bacteria are causing the symptoms and to identify patients who may require further investigation because of an underlying problem.
Can cystitis be diagnosed from symptoms alone?
In many women with typical symptoms, the answer is yes.
If an otherwise healthy woman develops a sudden onset of:
- burning when passing urine;
- urinary frequency;
- urinary urgency; and
- no vaginal discharge or irritation,
there is a high likelihood that she has acute uncomplicated bacterial cystitis.
Current clinical guidelines recognise that, in these situations, treatment may sometimes be started without waiting for laboratory confirmation, particularly if symptoms are typical and there are no features suggesting a more complicated infection.
However, symptoms alone become less reliable in:
- men;
- pregnant women;
- children;
- recurrent infections;
- urinary catheters;
- older adults;
- patients with weakened immune systems; and
- people with symptoms that do not improve as expected.
What is a urine dipstick test?
A urine dipstick is a simple test performed on a fresh urine sample. A chemically treated strip is dipped into the urine, changing colour if certain substances are present.
The dipstick commonly looks for:
- leucocytes (white blood cells), which suggest inflammation;
- nitrites, which indicate that certain bacteria have converted nitrates naturally present in urine into nitrites;
- blood;
- protein;
- glucose; and
- several other markers.
The test is quick and useful in many situations, but it is not perfect.
A positive dipstick does not always mean a urinary tract infection is present, while a negative dipstick does not completely exclude one.
For example, not all bacteria produce nitrites, and some patients with genuine bacterial cystitis have negative dipstick results.
This is why the dipstick should always be interpreted alongside your symptoms rather than in isolation.
When is a urine culture needed?
A urine culture is the most reliable way of confirming a bacterial urinary tract infection.
The urine sample is sent to a laboratory where any bacteria present are allowed to grow. This identifies:
- the exact organism causing the infection; and
- which antibiotics are likely to be effective.
A urine culture is particularly important if:
- symptoms keep coming back;
- you are pregnant;
- you are male;
- you have a urinary catheter;
- symptoms are severe;
- treatment has not worked;
- unusual bacteria are suspected; or
- there is concern about antibiotic resistance.
Culture results usually take 24–72 hours, depending on the organism.
Can you have cystitis with a negative urine culture?
Yes.
A negative urine culture does not always mean that your symptoms are imaginary or that nothing is wrong.
Possible explanations include:
- antibiotics started before the urine sample was collected;
- bacteria present in very small numbers;
- bacteria that are difficult to grow using standard laboratory techniques;
- bladder pain syndrome (interstitial cystitis);
- overactive bladder;
- pelvic floor dysfunction;
- sexually transmitted infections; or
- other causes of bladder inflammation.
Persistent urinary symptoms with repeatedly negative cultures should prompt further assessment rather than repeated empirical antibiotic treatment.
Do I need blood tests?
Most people with uncomplicated cystitis do not need blood tests.
However, blood tests may be recommended if:
- you appear seriously unwell;
- There is concern about a kidney infection
- sepsis is suspected;
- kidney function needs to be assessed; or
- another medical condition may be contributing to the infection.
These tests help assess the severity of illness rather than diagnose uncomplicated cystitis itself.
When are scans or cystoscopy needed?
Imaging and flexible cystoscopy are not required for most people experiencing a simple first episode of cystitis.
However, further investigation may be appropriate if:
- infections keep returning;
- visible blood in the urine persists;
- bladder stones are suspected;
- there are symptoms of urinary obstruction;
- the bladder does not empty completely;
- recurrent infections occur in men;
- kidney infections are recurring; or
- there is concern about another underlying bladder or urinary tract condition.
Possible investigations include:
- ultrasound, to assess the kidneys and bladder;
- measurement of post-void residual urine, to check how well the bladder empties;
- CT scanning, particularly when stones or anatomical abnormalities are suspected; and
- flexible cystoscopy, which allows a urologist to examine the inside of the bladder using a thin flexible camera.
The aim of these investigations is not simply to confirm the diagnosis of cystitis but to identify any underlying condition that may be responsible for repeated infections or persistent symptoms.
Can cystitis be mistaken for another condition?
Yes.
Several conditions can produce symptoms that closely resemble bacterial cystitis.
These include:
- bladder pain syndrome (interstitial cystitis);
- overactive bladder;
- kidney stones;
- bladder stones;
- sexually transmitted infections;
- vaginal infections;
- chronic prostatitis in men;
- bladder cancer; and
- pelvic floor dysfunction.
This is one reason why symptoms that persist despite appropriate treatment, or repeatedly return with negative urine cultures, should be investigated rather than simply treated with repeated courses of antibiotics.
How is bacterial cystitis treated?
The treatment of bacterial cystitis depends on how severe your symptoms are, whether the infection is uncomplicated or complicated, and whether you have any risk factors for developing a more serious infection.
For most otherwise healthy women with uncomplicated bacterial cystitis, treatment aims to:
- relieve symptoms as quickly as possible;
- eliminate the bacterial infection;
- prevent the infection from spreading to the kidneys; and
- reduce the risk of recurrent infections while avoiding unnecessary antibiotic use.
Current NICE and European Association of Urology (EAU) guidance also emphasise antimicrobial stewardship. This means using antibiotics only when they are likely to provide meaningful benefit, helping to reduce antibiotic resistance and unnecessary side effects.
Do I always need antibiotics?
Not always.
Many uncomplicated bladder infections improve naturally because the body's immune system is able to clear the infection.
Research has shown that some women recover without antibiotics, although symptoms usually last longer and there is a slightly higher chance that the infection will persist or progress.
For women with mild symptoms, a delayed antibiotic prescription may sometimes be appropriate. This allows treatment to be started if symptoms worsen or fail to improve over the following few days.
However, antibiotics are usually recommended when:
- symptoms are moderate or severe;
- you are pregnant;
- you are male;
- you have diabetes or a weakened immune system;
- there is concern that the infection is becoming more complicated; or
- you have signs suggesting the infection may be spreading beyond the bladder.
The decision should always be based on the individual patient rather than a single rule.
Which antibiotics are used?
The choice of antibiotic depends on several factors, including:
- local antibiotic resistance patterns;
- allergies;
- pregnancy;
- previous urine culture results;
- kidney function; and
- whether the infection is uncomplicated or complicated.
For this reason, there is no single antibiotic that is suitable for everyone.
When a urine culture has been performed, treatment can often be adjusted to target the specific bacteria responsible for the infection.
Can cystitis get better without antibiotics?
Yes.
Some uncomplicated infections resolve spontaneously.
However, antibiotics generally shorten the duration of symptoms and reduce the risk of the infection persisting or progressing.
NICE evidence suggests that women with uncomplicated cystitis treated with an effective antibiotic experience symptoms for an average of around 3.3 days, compared with approximately 4.9 days without antibiotic treatment.
Although this difference may appear modest, it can be significant for someone experiencing severe burning, urinary urgency and frequent trips to the toilet.
What can I do to relieve symptoms?
While the infection is settling, several simple measures may help improve comfort.
These include:
- drinking enough fluid to avoid dehydration;
- taking paracetamol if pain relief is needed and appropriate for you;
- avoiding drinks that seem to worsen symptoms, such as excessive caffeine or alcohol in some people; and
- emptying the bladder regularly rather than delaying urination.
Drinking large volumes of water does not "flush out" bacteria once an infection has become established, but maintaining normal hydration supports overall urinary tract health and helps prevent dehydration.
How long does treatment take?
Most antibiotic courses for uncomplicated bacterial cystitis are relatively short.
Many patients notice improvement within 24 to 48 hours, although it is common for burning or urinary frequency to take several days to settle completely.
If symptoms are worsening rather than improving after treatment has started, or if they persist after completing the antibiotic course, further assessment may be required to confirm the diagnosis, review urine culture results or look for another underlying cause.
Why is it important not to overuse antibiotics?
Antibiotics have transformed the treatment of urinary tract infections, but they should be used responsibly.
Every course of antibiotics places pressure on bacteria to develop resistance. Over time, this can make future infections more difficult to treat and reduce the effectiveness of commonly used antibiotics.
Repeated antibiotic use may also disrupt the body's normal bacterial communities, increasing the risk of problems such as antibiotic-associated diarrhoea and other infections.
For patients who experience recurrent cystitis, the goal is therefore not simply to prescribe repeated antibiotics, but to understand why infections are recurring and, where possible, prevent them from happening in the first place.
When might I need to be admitted to hospital?
Most people with uncomplicated bacterial cystitis can be treated at home.
Hospital assessment may be necessary if:
- there are signs of a kidney infection;
- Sepsis is suspected;
- You are unable to keep fluids or medication down because of vomiting
- severe pain cannot be controlled;
- you have a significantly weakened immune system; or
- There is concern about urinary obstruction or another serious complication.
These situations are uncommon but require prompt medical assessment because they may need intravenous antibiotics, imaging or specialist urological treatment.
When should I worry about cystitis, and can it be prevented?
Most people with uncomplicated bacterial cystitis begin to feel better within 24 to 48 hours of starting appropriate treatment, although burning when passing urine and urinary frequency may take several days to settle completely.
Research suggests that symptoms usually last around 3 days when treated with an effective antibiotic, compared with approximately 5 days without antibiotic treatment. However, recovery varies from person to person, and some bladder irritation may persist briefly even after the infection has cleared.
When should I seek urgent medical attention?
Although uncomplicated cystitis is usually a mild infection, certain symptoms suggest that the infection may have spread beyond the bladder or that another serious condition may be present.
Urgent medical assessment is recommended if you develop:
- a fever above 38°C;
- shaking chills or rigors;
- pain in the side or back below the ribs (loin pain);
- nausea or persistent vomiting;
- confusion, particularly in older adults;
- difficulty passing urine or complete urinary retention;
- severe pain that continues to worsen; or
- symptoms that fail to improve despite appropriate treatment.
These symptoms may indicate a kidney infection (pyelonephritis), urinary obstruction or, more rarely, sepsis, a serious reaction to infection that requires urgent treatment.
Why does cystitis keep coming back?
For some people, cystitis is not a one-off event.
A recurrent urinary tract infection is generally defined as:
- two or more infections within six months, or
- three or more infections within one year.
Recurrent infections often occur because an underlying factor has not been addressed.
Common reasons include:
- menopause and reduced oestrogen levels;
- incomplete bladder emptying;
- an enlarged prostate in men;
- bladder stones;
- urinary catheters;
- diabetes;
- bacteria surviving within the bladder lining;
- changes in the urinary and bowel microbiome; and
- increasing antibiotic resistance.
Successfully treating recurrent cystitis therefore involves more than prescribing repeated antibiotics. The most effective long-term strategy is identifying and correcting the underlying cause wherever possible.
Can cystitis be prevented?
Although not every infection can be prevented, several measures may reduce the risk of future episodes.
These include:
- maintaining good hydration;
- avoiding unnecessarily delaying urination;
- managing constipation;
- ensuring the bladder empties properly;
- considering vaginal oestrogen after the menopause when appropriate;
- reducing unnecessary antibiotic exposure; and
- investigating recurrent infections to identify any underlying abnormalities.
For people who continue to experience recurrent infections despite these measures, several non-antibiotic preventive treatments are now available. These include methenamine hippurate (Hiprex®), hyaluronic acid bladder instillations, immunoactive therapies and other emerging strategies.
Rather than discussing these treatments briefly here, I have covered each one in detail within dedicated articles so that patients can better understand the advantages, disadvantages and evidence supporting each option.
Frequently asked questions about cystitis
Can cystitis go away on its own?
Yes. Some mild cases of uncomplicated bacterial cystitis improve without antibiotics. However, antibiotics usually shorten the duration of symptoms and reduce the risk of the infection progressing. Anyone with severe symptoms, recurrent infections or risk factors for complications should be assessed promptly.
Can men get cystitis?
Yes, although it is much less common than in women. Because bacterial cystitis is uncommon in men, recurrent infections often require investigation to identify an underlying cause, such as an enlarged prostate, bladder stones or chronic bacterial prostatitis.
Is cystitis contagious?
No. Cystitis is not contagious and cannot be passed from one person to another through normal everyday contact. It is also not considered a sexually transmitted infection, although sexual activity can increase the risk of bacteria entering the bladder in some women.
Can stress cause cystitis?
Stress does not directly cause bacterial cystitis. However, it can worsen bladder symptoms, reduce the body's ability to cope with illness and sometimes aggravate conditions such as bladder pain syndrome, which can mimic the symptoms of cystitis.
Can cystitis affect the kidneys?
If a bacterial bladder infection spreads from the bladder to the kidneys, it can cause pyelonephritis, a kidney infection. This is uncommon but more serious than uncomplicated cystitis and usually causes fever, loin pain and feeling generally unwell.
Why do my urine tests keep coming back negative?
Persistent urinary symptoms with negative urine cultures may suggest another condition, such as bladder pain syndrome, overactive bladder, pelvic floor dysfunction or, occasionally, bacteria that are difficult to detect using standard laboratory techniques. Persistent or recurrent symptoms should be investigated rather than repeatedly treated with antibiotics.
Is blood in the urine always caused by cystitis?
No. Although cystitis can cause blood in the urine, visible haematuria can also be caused by kidney stones, bladder stones, enlarged prostate, kidney disease or bladder cancer. Blood in the urine that persists after treatment or occurs without infection should always be investigated.
Cystitis myths and facts
Myth: Cystitis and urinary tract infection mean exactly the same thing.
Fact: Cystitis means inflammation of the bladder. Although bacterial infection is the commonest cause, the bladder can also become inflamed without infection.
Myth: Every episode of cystitis needs antibiotics.
Fact: Not always. Some uncomplicated infections resolve naturally, while current guidelines emphasise using antibiotics appropriately to reduce antimicrobial resistance.
Myth: Drinking lots of water will wash the infection away.
Fact: Good hydration is important, but once bacteria have established an infection, simply drinking excessive amounts of water is unlikely to eliminate it.
Myth: Only women develop cystitis.
Fact: Men can also develop cystitis. However, because it is less common, recurrent infections in men often warrant further investigation to identify an underlying cause.
Myth: Once cystitis has been treated, it will not come back.
Fact: Unfortunately, recurrent infections are common. Around one in four women who experience a urinary tract infection will go on to develop recurrent episodes, highlighting the importance of identifying and managing the underlying cause.
What is cystitis? Key points
Cystitis is one of the commonest conditions affecting the urinary tract, but it is often misunderstood. Although most cases are caused by a bacterial infection of the bladder, cystitis simply means inflammation of the bladder, and not every episode is due to bacteria.
For most people, uncomplicated bacterial cystitis responds well to appropriate treatment and resolves within a few days. However, recurrent infections, persistent urinary symptoms or infections occurring in men should prompt consideration of an underlying cause rather than repeated courses of antibiotics alone.
Understanding why cystitis develops is the first step towards choosing the correct treatment. Whether the cause is bacterial infection, hormonal changes after the menopause, incomplete bladder emptying or another bladder condition, identifying and addressing the underlying problem offers the best chance of preventing future episodes.
As our understanding of the urinary microbiome, recurrent infection and non-antibiotic preventive treatments continues to evolve, the management of cystitis is becoming increasingly personalised. Rather than simply treating each infection as it occurs, modern care focuses on accurate diagnosis, responsible antibiotic use and long-term prevention tailored to the individual patient.
About Mr Edward Calleja
Mr Edward Calleja is a consultant urological surgeon specialising in the diagnosis and treatment of urinary tract infections, recurrent cystitis, prostatitis, enlarged prostate and robotic surgery for prostate and bladder cancer. He has a particular interest in evidence-based, non-antibiotic strategies for preventing recurrent urinary tract infections and reducing unnecessary antibiotic use.
His patient information articles are written using current NICE and European Association of Urology (EAU) guidance together with high-quality peer-reviewed medical research. They are designed to explain complex urological conditions in clear, straightforward language while helping patients understand the reasons behind different investigations and treatments.
References
Clinical guidelines
- European Association of Urology. EAU Guidelines on Urological Infections. Latest edition. Available at: https://uroweb.org/guidelines/urological-infections
- National Institute for Health and Care Excellence (NICE). Urinary tract infection (lower): antimicrobial prescribing (NG109). Available at: https://www.nice.org.uk/guidance/ng109
- National Institute for Health and Care Excellence (NICE). Urinary tract infection (recurrent): antimicrobial prescribing (NG112). Available at: https://www.nice.org.uk/guidance/ng112
Key reviews
- State-of-the-art review of urinary tract infections. European Urology Focus. 2025.
- Floege J, et al. Cystitis. Comprehensive review. 2023.
- American Academy of Family Physicians. Diagnosis and Treatment of Acute Uncomplicated Cystitis. American Family Physician. 2011.
Selected research
- Recent research into the urinary microbiome and recurrent urinary tract infection.
- Recent research into intracellular bacterial communities and recurrent cystitis.
- Review of ketamine-associated cystitis.
- Review of immune checkpoint inhibitor-associated cystitis.
- Review of emphysematous cystitis.
