Non-Specific Urethritis (NSU)
Urethritis is inflammation of the urethra - the tube that carries urine from the bladder out of the body.
It's usually caused by infection, although this is not always the case. The term NSU is used when the cause of the urethritis has not yet been identified.
NSU can have a number of possible causes, but it is estimated that the STI chlamydia is responsible for nearly half of all male cases.
Urethritis is one of the most common reasons for men to visit their local sexual health clinic. It's more difficult to diagnose urethritis in women because it may not cause as many symptoms.
Tests and treatment
Men with symptoms will be offered a urethral swab (like a cotton wool bud) to check for NSU.
It's usually treated with antibiotics and the symptoms usually go away within two weeks.
It's important that past and current sexual partners are also treated to prevent any infection spreading to other people.