Gonorrhoea: From Symptoms to Treatment

A 23-year-old man attends a sexual health service with a two-day history of burning when he passes urine and a thick yellow-green discharge from his penis. He has recently had sex with a new partner and condoms were not used every time. He feels otherwise well and has no testicular pain, rash or joint symptoms.

What might his symptoms suggest?

Dysuria and purulent urethral discharge make urethritis very likely. Gonorrhoea would be high on the differential because penile urethral gonorrhoea commonly produces noticeable symptoms, but the appearance of the discharge cannot confirm the organism on its own. Chlamydia and other causes of urethritis still need to be considered, and more than one sexually transmitted infection can be present at the same time.

The presentation can be much quieter at other anatomical sites. Endocervical infection may cause altered vaginal discharge, post-coital or intermenstrual bleeding and lower abdominal discomfort, but may also cause no symptoms. Rectal gonorrhoea is often asymptomatic, although pain, discharge, bleeding or tenesmus can occur. Pharyngeal infection is also usually asymptomatic. That difference is worth keeping in mind because someone with obvious urethral symptoms may also have infection elsewhere that they cannot feel.

What is happening and why?

Gonorrhoea is caused by Neisseria gonorrhoeae, a Gram-negative diplococcus that infects mucosal surfaces including the urethra, endocervix, rectum, pharynx and conjunctiva. When the bacteria reach a susceptible mucosal surface, structures on their outer surface help them attach to the epithelial cells rather than simply being washed away. Type IV pili help with the first attachment, while other surface proteins strengthen the interaction with the cell. You do not need to memorise every bacterial protein to understand the clinical picture. The important part is what happens next: the presence of the organism triggers a strong local inflammatory response and large numbers of neutrophils move into the infected tissue.

That neutrophil response helps explain the thick purulent discharge our patient has noticed. Pus contains large numbers of neutrophils alongside bacteria and cellular debris. N. gonorrhoeae is particularly successful at persisting despite this inflammatory response, and it can alter some of the structures displayed on its surface. Previous infection therefore does not give reliable long-term immunity, so someone who has had gonorrhoea before can acquire it again.

Gonorrhoea is the second most commonly diagnosed bacterial STI in the UK. Surveillance is collected separately across the four UK nations, so individual annual totals should be interpreted within their national systems rather than combined as though they were one directly comparable dataset. To give some sense of the burden, Public Health Scotland recorded 4,509 diagnoses in Scotland in 2025. Across the UK, younger adults and gay, bisexual and other men who have sex with men are among the groups with higher rates of diagnosis, although gonorrhoea can affect anyone exposed to the infection.

What else would you want to know?

For our patient, we need to know when the symptoms started and when the possible exposure occurred, but we also need to ask beyond the urethral symptoms. Has he had any testicular or scrotal pain, rectal symptoms, sore throat, fever, rash, joint pain or eye symptoms? Severe unilateral scrotal pain needs careful assessment because epididymo-orchitis is possible, but testicular torsion is an important alternative diagnosis that requires urgent surgical assessment. Joint symptoms, tenosynovitis or a new pustular rash would raise a different concern about infection spreading beyond the original mucosal site.

The sexual history tells us where infection may be present. Ask about recent partners, condom use and whether he has had vaginal, anal or oral sex, including which anatomical sites were exposed. Previous STIs, recent antibiotic use, drug allergies and any previous gonorrhoea treatment are also relevant. The questions should be asked without judgement and with a clear clinical purpose. A patient may come in because of penile discharge, but if oral or anal exposure is not discussed, an asymptomatic pharyngeal or rectal infection can easily be missed.

What investigations are recommended?

Nucleic acid amplification testing (NAAT) is highly sensitive for detecting N. gonorrhoeae genetic material. For someone with penile urethral symptoms, first-catch urine is commonly used for NAAT, while vulvo-vaginal sampling is used for genital testing in people with vaginal anatomy. Rectal and pharyngeal samples are taken according to exposure and current guidance. BASHH also recommends pharyngeal testing for people diagnosed with urogenital gonorrhoea and their contacts because throat infection is commonly asymptomatic.

With gonorrhoea, however, NAAT is only part of the investigation. We also want a culture before antibiotics wherever possible. NAAT tells us that gonococcal genetic material is present, whereas culture grows the living bacterium. Once the organism is growing in the laboratory, it can be tested against antibiotics to see which drugs it is susceptible or resistant to. This is particularly important with gonorrhoea because antimicrobial resistance has progressively removed many antibiotics that were once reliable treatments.

In a specialist sexual health setting, microscopy can sometimes give an immediate clue. If intracellular Gram-negative diplococci are seen in urethral discharge from a symptomatic patient like this one, gonorrhoea can be diagnosed presumptively while culture and other testing continue. Microscopy is much less sensitive at some other sites, so a negative slide cannot simply rule gonorrhoea out. Anyone diagnosed with gonorrhoea should also be offered appropriate testing for other STIs, including chlamydia, syphilis and HIV.

How could gonorrhoea be managed?

Current BASHH guidance recommends ceftriaxone 1 g intramuscularly as a single dose as first-line treatment for uncomplicated anogenital and pharyngeal gonorrhoea in adults. Treatment can differ when ceftriaxone cannot be used, when antimicrobial susceptibility results allow another option to be selected, or when the infection is complicated. Pregnancy, allergy history and the site and severity of infection also need to be considered.

Not everyone requires a routine test of cure after uncomplicated anogenital infection treated successfully with ceftriaxone when susceptibility is known. BASHH recommends test of cure in particular situations, including persistent symptoms, pharyngeal infection, unknown antimicrobial susceptibility, treatment with something other than ceftriaxone and pregnancy. If symptoms continue after treatment, culture becomes particularly important because the clinician needs to distinguish reinfection from possible treatment failure and antimicrobial resistance.

Resistance is a much bigger part of the gonorrhoea story than it is for many other common STIs. N. gonorrhoeae has developed resistance to successive antibiotic classes over time, leaving ceftriaxone as the main empirical treatment in current UK practice. The pharynx is especially relevant because gonococci can live alongside other Neisseria species there and can exchange genetic material. This is one route by which resistance-associated genes can enter gonococcal populations. Resistant gonorrhoea remains uncommon compared with the total number of infections, but resistant strains, including ceftriaxone-resistant isolates, continue to be detected in the UK. That is why obtaining culture and susceptibility testing is part of good gonorrhoea management rather than an optional extra.

What should we explain to the patient?

Our patient needs to understand that gonorrhoea is a bacterial STI that can be treated, but treatment does not give future immunity. He can acquire it again. He should know what treatment he is receiving, what follow-up is needed and when to return if his symptoms do not settle. BASHH advises avoiding sexual intercourse until seven days after both the patient and their partner or partners have completed treatment.

Partner notification is part of the clinical management because partners may have infection without symptoms and can continue to transmit it or reinfect the patient. Sexual health services can help with this confidentially. It is also worth explaining why samples may have been taken from places that were not causing symptoms, particularly the throat or rectum. The absence of discomfort does not mean those sites are free from infection. Advice about condoms, future STI testing and reducing transmission can then be tailored to the patient rather than delivered as a generic lecture.

What could happen if it is not appropriately managed?

Gonorrhoea can spread beyond the original mucosal site. Infection ascending from the endocervix can contribute to pelvic inflammatory disease (PID), with subsequent risks including chronic pelvic pain, tubal damage, ectopic pregnancy and subfertility. Infection involving the urethra can spread to the epididymis and cause epididymitis or epididymo-orchitis. Gonococcal eye infection is uncommon but particularly urgent because the organism can damage the cornea rapidly, so a very red eye with copious purulent discharge needs urgent specialist assessment.

Occasionally the organism enters the bloodstream and causes disseminated gonococcal infection (DGI). A patient may develop migratory joint pain, tenosynovitis and skin lesions, or present with septic arthritis. Severe systemic infection can occur. Pregnancy brings an additional concern because gonorrhoea can be passed to a baby during birth and cause ophthalmia neonatorum, a potentially serious neonatal conjunctivitis.

There is also a public-health consequence when infection is missed or incompletely managed. Asymptomatic infection can continue to circulate between partners, and untreated contacts can reinfect someone who has already completed treatment. Antimicrobial resistance adds another layer because resistant strains can also spread through sexual networks. Correct site-specific testing, culture, effective treatment, partner notification and appropriate follow-up therefore protect both the individual patient and the wider population.

A little extra: gonorrhoea is very particular about its host

Neisseria gonorrhoeae is an exclusively human pathogen, with humans as its only natural host. It is highly adapted to human mucosal surfaces and can vary some of the structures exposed on its surface, helping it persist despite the immune response. Unlike infections that circulate between animals and humans, there is no known animal reservoir maintaining gonorrhoea: transmission is human to human. (Quillin & Seifert, 2018)

References

British Association for Sexual Health and HIV (BASHH) (2025) UK National Guideline for the Management of Infection with Neisseria gonorrhoeae. Available at: BASHH gonorrhoea guideline.

Public Health Scotland (2026) Sexually transmitted infections in Scotland 2016 to 2025. Available at: Public Health Scotland STI statistics.

Quillin, S.J. and Seifert, H.S. (2018) ‘Neisseria gonorrhoeae host adaptation and pathogenesis’, Nature Reviews Microbiology, 16(4), pp. 226–240. doi: 10.1038/nrmicro.2017.169.

Stevens, J.S. and Criss, A.K. (2018) ‘Pathogenesis of Neisseria gonorrhoeae in the female reproductive tract: neutrophilic host response, sustained infection, and clinical sequelae’, Current Opinion in Hematology, 25(1), pp. 13–21. doi: 10.1097/MOH.0000000000000394.