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Non-specific urethritis (NSU)


Non-specific urethritis (NSU) is one of the most common sexually transmitted infections in men. If left untreated it can cause arthritis. It is also known as non-gonococcal urethritis (NGU) when it is not caused by gonorrhoea.

‘Urethritis’ means ‘inflammation of the urethra’ (the tube inside the penis that urine comes down).

‘Non-specific’ means the exact cause of the inflammation isn’t known, but it is caused by bacteria (often chlamydia) picked up from a partner’s mouth, vagina, rectum or penis during sex.

Women can also contract NSU but it can be harder to diagnose in women as it does not cause many symptoms.

This page talks about NSU in men.

Symptoms of non-specific urethritis:

There may be no symptoms but up to three weeks after becoming infected a man might experience the following:

  • a whitish discharge from his penis
  • urinating (peeing) frequently
  • pain or burning when urinating
  • irritation and soreness at the tip of his penis.

How it's passed on

NSU is usually caused by bacteria.

They live inside a partner’s mouth, vagina, penis or rectum and get into a man’s penis when he has unprotected oral, vaginal or anal sex.

He might also carry the bacteria on his fingers to his penis after touching an infected part of his own or someone else’s body.

Using condoms cuts the risk of NSU, which can also be caused by unprotected oral sex. Sometimes NSU is inflammation caused by friction from masturbation and sex, or even a reaction to things like soap.

If a man has HIV, having untreated NSU could make it more likely he will pass on HIV during unprotected sex. But if HIV drugs have made his viral load undetectable then NSU or other infections don’t appear to make him more likely to pass on HIV.

Tests and treatment

There’s a urine test for NSU or a sample can be taken from the opening of the penis using a swab (small cotton bud). This might be uncomfortable for a second or two.

A course of antibiotics will cure NSU. Sex should be avoided until the treatment is finished to avoid passing it on. Sexual partners also need to be checked and treated - a clinic can contact them anonymously.

Untreated NSU sometimes causes serious problems such as arthritis.

Most people get tested and treated for infections like NSU at sexual health (or ‘GUM’) clinics. It is free and confidential - no-one else, including your GP, will be told about your visit. Some GP surgeries also test for and treat these infections.

The more people you have sex with (especially unprotected sex), the more chance you have of getting infections like NSU. You can have them without knowing, so regular check-ups are a good idea, especially if you are starting a new relationship and/or you want to stop using condoms with your partner.

Next: Pubic lice ››

‹‹ Back to: Molluscum



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The Information Standard: Certified member

This article was last reviewed on 14/9/2015 by Anna Peters

Date due for the next review: 14/9/2018

Content Author: R. Scholey

Current Owner: Health Promotion

More information:

Health Service Executive, Non-specific urethritis

NHS Choices, Non-gonococcal urethritis, October 2014

NHS Choices, Non-specific urethritis - Symptoms, September 2014

NHS Choices, Causes of non-gonococcal urethritis, September 2014

FPA, Non-specific urethritis, 2015

NAM aidsmap, No one with an undetectable viral load, gay or heterosexual, transmits HIV in first two years of PARTNER study, by Gus Cairns, March 2014

NHS Choices, Non-gonococcal urethritis - Complications, September 2014

NHS Choices, Non-gonococcal urethritis, September 2014

NHS Choices, Open your eyes to STIs, October 2013

NHS Choices, STI symptoms that need checking, November 2013

Hunter, H. Color Atlas and Synopsis of Sexually Transmitted Diseases (second edition) McGraw-Hill, Handsfield, 2001

McMillan A, Scott GR. Sexually Transmitted Infections (second edition), Churchill, Livingstone, 2000

BASHH NGU guidelines, BASHH

BASHH NSU guidelines, BASHH (2007)

British Association for Sexual Health and HIV, Clinical Effectiveness Group, UK National Guideline on the Management of Nongonococcal Urethritis, (2007, Updated Dec 2008)


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