Viral Non-Specific Urethritis

Urethritis can be caused by a huge number of infectious and non-infectious factors. While gonococcal urethritis is restricted to being a consequence of infection with gonococcal bacteria, non-specific urethritis can be attributed to injury or infection with bacteria, viruses, or protozoa. In this article we look at viral causes of NSU (non-specific urethritis), and how viral infections may differ from other causes of the condition.

Viral causes of NSU

Two relatively common viruses which can potentially cause non-specific urethritis are the adenovirus and herpes simplex. Viruses are quite different to bacteria in that while the latter are living, microscopic organism with a range of biological functions, viruses are essentially little more than self-replicating machinery in a protein coating. Despite their potentially severe effects on our bodies, viruses are amazingly simple pathogens.


The adenovirus exists in dozens of subtypes which can potentially cause a huge range of conditions including gastroenteritis, bronchitis, and genital infections. Genital infections can be sexually transmitted, and are caused by a number of subtypes of the virus.

Herpes simplex is a more well-known virus which can attribute its fame to cold sores and genital herpes. The latter condition is more relevant to non-specific urethritis as it is a sexually transmitted virus which can cause the inflammation of the urethra which is the heart of NSU.

Both viral infections are, as mentioned above, sexually transmissible. Because of the biological role played by the urethra and its place within the genitals, intercourse will expose the urethra to infectious agents like these viruses, resulting in the inflammatory condition we know as non-specific urethritis. This inflammation is a consequence of the body’s defences reacting to the presence of an invading agent, and serves as an immune mechanism to isolate the site of infection and expose it to a range of different important defensive measures.

Viral infection causing NSU will present with the symptoms typical of the condition. While many patients, mostly women, suffering from the condition will be asymptomatic, a significant number will experience a number of characteristic symptoms:

  • Painful urination usually described as a burning sensation.
  • Pain at the end of the urethra/tip of the penis.
  • A milky discharge (usually from men).

Treating viral NSU

Interestingly enough treatment for NSU caused by viruses will follow the same route as NSU caused by bacteria here in the UK. You are most likely to be offered a single dose of azithromycin, or a week long regimen of doxycycline. For the latter it is important that you follow the dosing regimen for the whole week even if your symptoms clear up early, although it will typically take about 2-3 weeks for this to occur.

As with any STI cause for NSU, once the condition has been diagnosed as having been caused by herpes simplex or adenovirus, it is important that you contact previous sexual partners to ensure that they get the treatment they need. These infections can be asymptomatic, but still need treatment to restrict their spread.

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