Urethritis is an inflammation of the urethra, the tube through which urine (and, in men, semen) passes. This inflammation can be caused by several sexually transmitted infections. Non-gonococcal urethritis (NGU) refers to urethritis that is not caused by Neisseria gonorrhoeae. Most commonly, this is caused by chlamydia and can affect both men and women. Another term, non-specific urethritis (NSU) means that urethritis is neither caused by Neisseria gonorrhoeae nor Chlamydia trachomatis. While the terms NGU and NSU are often used interchangeably, it is not correct to do so. However, NSU can have some non-sexual causes. If left untreated, NGU/NSU can cause reduced fertility, inflammation of the eyes and joints, and can increase the likelihood of passing on HIV.

NGU and NSU are almost always caused by an infection which has been passed on during unprotected anal, oral and vaginal sex. Very rarely NSU can be caused by excessive friction during masturbation or sex, an allergic reaction to soap or detergent, or by drinking too much alcohol.

Untreated NGU/NSU can make a person with HIV more infectious, as the infections which cause it can increase the number of HIV-infected cells in genital fluids. Having NGU/NSU can also make it more likely that an HIV-negative person will be infected with HIV if they are exposed to the virus.

Using a condom for anal, oral or vaginal sex is an effective way of avoiding the infections which cause NGU/NSU or passing NGU/NSU on to somebody else. People who are sexually active are advised to have regular check-ups where they will be tested for NGU/NSU and other sexually transmitted infections. Most HIV treatment centres have an associated sexual health clinic where free and confidential treatment can be obtained without referral from your GP or your HIV doctor.

Symptoms of NGU/NSU normally develop within a week or so of infection, although some irritants, such as soap, can cause symptoms to occur almost immediately. However it is estimated that as many as 50% of men with NGU/NSU have no symptoms at all.

When symptoms do occur, they normally consist of pain or a burning sensation when passing urine, and a white or cloudy discharge which may be particularly noticeable first thing in the morning. Needing to pass urine more often is also another symptom.

A general sexual health check-up at a genitourinary medicine (GUM) or a sexual health clinic, will include a test for NGU/NSU. GUM clinics are free, confidential and open access. Some HIV clinics also offer sexual health screening. NGU/NSU is diagnosed by either a swab test or by checking a urine sample or sometimes both.

In many cases it will be possible to tell instantly if NGU is present, but it can take up to a week for tests to show if chlamydia is present.

NGU/NSU is treated with antibiotics. Normally this consists of a seven-day course of doxycycline or a single dose of azithromycin. It is important to take all your tablets to ensure that the infection has been cleared from your body. Symptoms may last for a few days after taking azithromycin as the antibiotic takes time to work.

When NGU/NSU is diagnosed, you may be given an opportunity to speak to a health adviser who can give you information about safer sex and how to avoid picking up or passing on sexually transmitted infections. Health advisers may also ask you to help them, where possible or practicable, to contact your sexual partners so they can be tested and treated too. This in turn, is intended to prevent you from becoming re-infected through continuing to have sex with someone who is themselves infected.

You may be asked to return a week later for a test to see that you have been cured. You are likely to be advised not to have sex (even with a condom) until your treatment period has finished. This is to prevent re-infection.