What Is Cystitis?

Cystitis simply means inflammation of the bladder. While most people hear “cystitis” and immediately think of bacterial urinary tract infections, the term actually covers a broader range of conditions. The bladder can become inflamed for many reasons: bacterial infection, chemical irritation, radiation damage, or causes we still don’t fully understand.

I find it helpful to think of cystitis as an umbrella term rather than a single diagnosis. When your GP says you have cystitis, the next question should always be: which type?

Types of Cystitis

Bacterial Cystitis (Urinary Tract Infections)

Bacterial cystitis is by far the most common form, accounting for the vast majority of cystitis cases. It occurs when bacteria (usually Escherichia coli from the gut) enter the urethra and colonise the bladder lining.

Women are particularly vulnerable because of their shorter urethras. According to NHS data, roughly half of all women will experience at least one UTI during their lifetime, and many will have recurrent episodes 1.

Common symptoms include:

A burning sensation when urinating
Needing to urinate more frequently
Feeling an urgent need to urinate even when the bladder is nearly empty
Cloudy, dark, or strong-smelling urine
Pain or pressure in the lower abdomen
Blood in the urine (haematuria)

Most uncomplicated bacterial cystitis responds well to a short course of antibiotics. However, if you experience recurrent UTIs, your doctor may recommend preventive strategies including increased fluid intake, post-coital voiding, or prophylactic antibiotics.

For those interested in natural prevention approaches, our articles on cranberry supplements and D-mannose cover the current evidence.

Interstitial Cystitis and Painful Bladder Syndrome

Interstitial cystitis (IC) is a different beast entirely from bacterial cystitis. It causes similar symptoms (urgency, frequency, bladder pain) but urine cultures come back negative. There’s no bacterial infection to treat, which is exactly the problem.

This frustrates patients and clinicians alike. The exact cause of IC remains unknown, though theories include defects in the bladder lining (the glycosaminoglycan layer), autoimmune dysfunction, and neurological hypersensitivity 2.

Painful bladder syndrome is sometimes used interchangeably with IC, though some specialists reserve it for cases where bladder wall changes aren’t visible on cystoscopy. Whatever we call it, the condition can make daily life difficult and is notoriously hard to manage.

Treatment approaches for IC/PBS may include:

Bladder instillations with hyaluronic acid or lidocaine
Oral medications such as amitriptyline or pentosan polysulfate
Dietary modifications (avoiding known bladder irritants)
Pelvic floor physiotherapy
Bladder training programmes

I should mention that IC is not simply “chronic cystitis” in the bacterial sense. Antibiotics won’t help and may actually worsen the condition by disrupting gut flora.

Radiation Cystitis

Radiation therapy for pelvic cancers (cervical, prostate, rectal, bladder) can damage the bladder lining, sometimes causing symptoms that appear months or years after treatment ends. This is called radiation cystitis, or in more severe cases involving significant bleeding, haemorrhagic cystitis.

The radiation damages blood vessels in the bladder wall, which can become fragile and prone to bleeding. Symptoms range from mild urgency and frequency to severe haematuria requiring hospitalisation.

Treatment options include:

Hyperbaric oxygen therapy (which has shown promise in promoting tissue healing)
Bladder instillations with hyaluronic acid (Cystistat, Gepan)
Pentosan polysulfate sodium (Elmiron)
Fulguration (cauterising bleeding vessels)
In severe cases, cystectomy (bladder removal) may be necessary

A systematic review found hyperbaric oxygen therapy resolved haematuria in approximately 80% of patients with radiation cystitis, though treatment requires multiple sessions over several weeks 3.

Chemotherapy-Induced Cystitis

Certain chemotherapy drugs, particularly cyclophosphamide and ifosfamide, can cause direct chemical damage to the bladder lining. The metabolite acrolein is the culprit. It’s excreted in urine and irritates bladder tissue.

This is why patients receiving these drugs are given mesna (2-mercaptoethane sulfonate sodium), which binds to acrolein in the urinary tract and neutralises it. The drug doesn’t reduce the cancer-fighting effects of chemotherapy; it simply protects the bladder.

BCG (Bacillus Calmette-Guérin) immunotherapy, used to treat early-stage bladder cancer, can also cause cystitis-like symptoms. This is actually a sign the treatment is working—the immune response that attacks cancer cells also irritates the bladder lining temporarily. Symptoms usually resolve within a few days of each treatment.

Cystitis Glandularis and Cystitis Cystica

These are terms describing how the bladder lining looks under cystoscopy, usually in response to chronic irritation or infection.

Cystitis cystica appears as small fluid-filled blisters on the bladder surface. Cystitis glandularis involves more substantial changes where the normal bladder cells (urothelium) transform into glandular tissue, giving the bladder a cobblestone appearance.

These changes are generally considered benign and reactive—the bladder is essentially trying to protect itself from ongoing irritation. However, they do indicate chronic inflammation that should be addressed, usually by treating underlying infections or removing sources of irritation (such as bladder stones or catheters).

There’s no direct relationship between cystitis glandularis and IC/PBS, though they occasionally coexist. Treatment focuses on eradicating any underlying infection with long-term antibiotics and removing other sources of chronic irritation.

Follicular Cystitis

This is a chronic inflammatory condition characterised by small nodules on the bladder mucosa and the formation of lymphoid follicles. It represents the bladder’s immune response to persistent infection or irritation.

Follicular cystitis is diagnosed by cystoscopy and biopsy. Treatment typically involves:

Antibiotics to control any underlying infection
Occasionally corticosteroids (such as prednisolone) to reduce inflammation
Addressing any contributing factors like bladder stones or foreign bodies

Eosinophilic Cystitis

This is a rare form of bladder inflammation where eosinophils (a type of white blood cell associated with allergic reactions) accumulate in the bladder wall. The cause is usually unknown, though it occurs more commonly in people with a history of allergies, asthma, or other eosinophilic disorders.

Symptoms can mimic IC/PBS or bacterial cystitis. Diagnosis requires a bladder biopsy showing eosinophilic infiltration.

Treatment may include:

Antihistamines
Antimuscarinics for urgency symptoms
Amitriptyline
Corticosteroids in more severe cases
Identifying and eliminating potential allergens

The condition is unpredictable. Some cases resolve spontaneously, others become chronic.

Trigonitis

Trigonitis refers to changes in the triangular area at the base of the bladder called the trigone, where the ureters enter and the urethra exits. During cystoscopy, the trigone appears reddened or shows squamous metaplasia (where normal bladder cells are replaced by skin-like cells).

Trigonitis is most commonly found in postmenopausal women or younger women with fluctuating oestrogen levels. It may be associated with chronic vaginal infections or simply hormonal changes.

The condition often causes no symptoms. When symptomatic, treatment options include:

Topical oestrogen therapy (particularly effective in postmenopausal women)
Antibiotics if infection is present
Anticholinergic medications for urgency
Electrocautery or laser treatment in selected cases

When to See a Doctor

Not every episode of bladder discomfort requires a GP visit, but certain symptoms warrant prompt medical attention:

Blood in your urine (visible or detected on a test)
Fever, chills, or back pain (suggesting the infection may have spread to the kidneys)
Symptoms that don’t improve within a few days
Frequent recurrences (more than two or three UTIs per year)
Symptoms during pregnancy
Symptoms in men (UTIs in men are less common and often indicate an underlying issue)

If you’re experiencing chronic bladder symptoms without positive urine cultures, ask your GP about referral to a urologist. Conditions like IC/PBS often go undiagnosed for years because practitioners assume negative cultures mean there’s no problem.

I’ve spoken with patients who were told “it’s all in your head” or “just drink more water” when they actually had IC. Don’t accept a brush-off if your symptoms are real and persistent. Keep a symptom diary, note what makes things better or worse, and bring this information to your appointments.

Prevention Strategies

For bacterial cystitis specifically, several strategies have reasonable evidence behind them:

Stay well hydrated (aim for clear or pale yellow urine)
Urinate regularly rather than holding it for extended periods
Wipe front to back after using the toilet
Urinate soon after sexual intercourse
Consider cranberry products. A 2023 Cochrane review found moderate-quality evidence that they reduce recurrent UTI risk, particularly in women 4
D-mannose may help prevent E. coli from adhering to the bladder wall, worth discussing with your doctor if you have recurrent UTIs

For IC/PBS and other non-infectious forms of cystitis, prevention focuses on identifying and avoiding personal triggers, which can include certain foods, beverages, stress, and hormonal fluctuations.

References

NHS. Urinary tract infections (UTIs). NHS website. https://www.nhs.uk/conditions/urinary-tract-infections-utis/
Marcu I, Campian EC, Tu FF. Interstitial Cystitis/Bladder Pain Syndrome. Semin Reprod Med. 2018;36(2):123-135.
Cardinal J, et al. Hyperbaric oxygen therapy for hemorrhagic radiation cystitis: a systematic review. Can Urol Assoc J. 2018;12(12):E497-E503.
Williams G, et al. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2023;4(4):CD001321.