Chlamydia / Gonorrhoea (Urethritis)

Urethritis is inflammation of the urethra — the tube that carries urine out of the body. It is most commonly caused by sexually transmitted infections (STIs), with Chlamydia trachomatis and Neisseria gonorrhoeae (the bacteria responsible for gonorrhoea) being the two most important and well-recognised causes. Both infections are common, frequently asymptomatic, and highly treatable — but if left undetected and untreated, they can cause serious complications including pelvic inflammatory disease, infertility, and chronic pelvic pain. Because symptoms can be mild or absent, regular screening is essential, especially if you are under 25 or have new partners.

Urethritis caused by gonorrhoea is called gonococcal urethritis. Urethritis caused by chlamydia or other non-gonorrhoeal organisms is called non-gonococcal urethritis (NGU). Both can cause identical symptoms, and the two infections frequently co-exist — around 20–40% of people diagnosed with gonorrhoea are also infected with chlamydia.

Chlamydia and gonorrhoea: key differences

Chlamydia (Chlamydia trachomatis) The most common bacterial STI globally. Most infections — particularly in women — produce no symptoms at all, which means many people are unaware they are infected and can unknowingly transmit the infection. When symptoms do occur, they typically develop within 7–21 days of exposure.

Gonorrhoea (Neisseria gonorrhoeae) Tends to produce more pronounced symptoms, particularly in men. Gonorrhoea is increasingly concerning due to emerging antibiotic resistance, which has narrowed effective treatment options significantly in recent years.

Both infections can affect the urethra, cervix, rectum, throat, and eyes. Extragenital infections — particularly in the throat and rectum — are often asymptomatic, which is why testing at all relevant sites based on sexual history is important. Either infection can be present without the other, but co-infection is common.

Symptoms

A key clinical challenge with both infections is that many people — especially those with chlamydia — have no symptoms at all.

In men, symptomatic urethritis typically causes:

Urethral discharge — ranging from clear or mucoid (chlamydia) to yellow-green or purulent (gonorrhoea)
Burning or pain on urination (dysuria)
Urethral itch or irritation
Redness or swelling at the tip of the urethra

In women, symptoms are more often absent or mild and non-specific:

Increased or unusual vaginal discharge
Burning on urination
Pain during sex
Pelvic or lower abdominal discomfort
Intermenstrual or post-coital bleeding

At other sites (pharynx, rectum, eyes):

Throat infections are usually asymptomatic
Rectal infections may cause discharge, discomfort, or rectal bleeding, or no symptoms
Conjunctivitis (eye infection) — rare but can be serious

Seek testing if:

You have any of the above symptoms, even if mild
You have been notified by a partner that they have tested positive
You are sexually active with new or multiple partners — many guidelines recommend routine screening even without symptoms

See a clinician urgently if:

You have severe pelvic or abdominal pain, high fever, or testicular swelling — these can indicate a spreading infection requiring prompt treatment

Causes and transmission

Both chlamydia and gonorrhoea are transmitted through unprotected sexual contact — vaginal, anal, or oral. Neither infection is spread through casual contact such as sharing toilets, towels, or utensils.

Risk factors include:

Unprotected sex (without a condom)
New or multiple sexual partners
Age under 25 — both infections disproportionately affect young adults
Previous STI — having one STI increases the likelihood of having another
Not attending regular STI screening

Gonorrhoea can be transmitted from mother to newborn during delivery, potentially causing neonatal conjunctivitis. Chlamydia can similarly be transmitted perinatally, causing conjunctivitis or pneumonia in newborns.

Complications

Untreated or inadequately treated chlamydia and gonorrhoea can cause significant complications, particularly in women where infections are more likely to be asymptomatic and therefore go undetected for longer.

In women:

Pelvic inflammatory disease (PID) — infection spreads to the uterus, fallopian tubes, and ovaries; a leading cause of chronic pelvic pain, ectopic pregnancy, and infertility
Fallopian tube scarring — even a single episode of PID can permanently affect fertility
Complications in pregnancy — increased risk of ectopic pregnancy, early pregnancy loss, preterm birth, and neonatal infection

In men:

Epididymo-orchitis — infection of the epididymis and testicle, causing pain, swelling, and in some cases infertility
Prostatitis — infection of the prostate gland

In anyone:

Disseminated gonococcal infection (DGI) — rare but serious; gonorrhoea spreads through the bloodstream causing joint pain, skin lesions, and rarely meningitis or endocarditis
Reactive arthritis — joint inflammation that can develop as a response to chlamydia infection
Increased HIV susceptibility — both infections increase the risk of acquiring and transmitting HIV

Diagnosis

Both infections are diagnosed by detecting the bacteria — symptoms alone are not reliable enough to confirm diagnosis or distinguish between infections.

Nucleic acid amplification test (NAAT), often called a PCR test — the most accurate and widely used method; detects the genetic material of both Chlamydia trachomatis and Neisseria gonorrhoeae. Can be performed on a first-void urine sample (not midstream), a self-collected swab, or a clinician-collected swab from the urethra, cervix, rectum, or throat depending on sexual history
Urinalysis — may show white blood cells (pyuria) and positive leukocyte esterase, suggesting urethral inflammation; however, standard urine culture will not detect either chlamydia or gonorrhoea. A negative standard urine culture does not rule out these infections
Gram stain of urethral discharge — can suggest gonorrhoea in symptomatic men by showing characteristic bacteria inside white blood cells; useful for rapid presumptive diagnosis in a clinical setting but not sufficient alone
Culture — less commonly used for chlamydia but important for gonorrhoea when antibiotic susceptibility testing is needed, particularly in suspected treatment failure or drug-resistant gonorrhoea

Testing for other STIs — including HIV, syphilis, and hepatitis B — is routinely recommended alongside chlamydia and gonorrhoea testing.

Treatment

Both infections are bacterial and are treated with antibiotics. Treatment should be started as soon as infection is confirmed — or, in high-risk situations, empirically while awaiting test results.

Chlamydia

Doxycycline 100mg twice daily for 7 days — the preferred first-line treatment per current guidelines. Take with plenty of water and avoid lying down immediately after to reduce oesophageal irritation
Azithromycin 1g as a single dose — an alternative, though doxycycline has higher cure rates for urogenital chlamydia in current evidence

Gonorrhoea

Ceftriaxone 500mg intramuscularly as a single dose — the current first-line treatment (1g for individuals weighing 150kg or more)
Dual therapy with doxycycline is recommended if chlamydia co-infection has not been excluded
Antibiotic resistance in gonorrhoea is a serious and growing public health concern; treatment guidelines are updated regularly, and local resistance patterns should guide prescribing

After treatment:

Abstain from sexual activity for 7 days after completing treatment and until all partners have been treated
All sexual partners from the relevant exposure window (typically 60 days prior to symptoms or diagnosis) should be notified, tested, and treated
A test of cure is recommended for gonorrhoea, particularly pharyngeal infection; retest for both infections at 3 months following treatment
Test for other STIs including HIV if not already done

FAQ

Can you have chlamydia or gonorrhoea without any symptoms? Yes — this is very common, particularly with chlamydia. The majority of women and a significant proportion of men with chlamydia have no symptoms. Regular screening is the only reliable way to detect asymptomatic infection.

Will a standard urine test or urine culture detect chlamydia or gonorrhoea? No. Standard urine culture tests for common bacteria such as E. coli and will not detect Chlamydia trachomatis or Neisseria gonorrhoeae. A NAAT (PCR-based test) performed on a first-void urine sample or swab is required. A negative standard urine culture does not rule out these infections.

Do I need to tell my partner if I test positive? Yes — partner notification is an important part of managing these infections. Partners need to be tested and treated to prevent reinfection and further transmission. Many clinics offer confidential partner notification services if you need support with this.

Can chlamydia or gonorrhoea come back after treatment? Reinfection can occur if you have sexual contact with an untreated partner or a new exposure — this is why treating all recent partners and retesting at 3 months is recommended. Persistent symptoms after treatment may also indicate a different infection such as Mycoplasma genitalium, or non-adherence to treatment, and should be assessed by a clinician.

Is gonorrhoea becoming resistant to antibiotics? Yes. Gonorrhoea has developed resistance to multiple antibiotic classes over time and treatment options have narrowed considerably. This makes it important to use the correct current first-line treatment, complete the full course, and attend for a test of cure after pharyngeal infection.

Related biomarkers

Standard urinalysis may show white blood cells (leukocytes) and positive leukocyte esterase in urethritis, which can prompt further STI-specific testing — but urinalysis alone cannot diagnose chlamydia or gonorrhoea. NAAT testing of urine or swabs is the definitive diagnostic test. Tracking urinalysis patterns in HealthMatters can help document the initial presentation and support follow-up monitoring, particularly for people who experience recurrent urogenital symptoms or who are managing multiple STI results over time.

(leukocytes) and positive leukocyte esterase in urethritis, which can prompt further STI-specific testing — but urinalysis alone cannot diagnose chlamydia or gonorrhoea. NAAT testing of urine or swabs is the definitive diagnostic test. Tracking urinalysis patterns in HealthMatters can help document the initial presentation and support follow-up monitoring, particularly for people who experience recurrent urogenital symptoms or who are managing multiple STI results over time.