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Epididymo-orchitis - the basics
Epididymo-orchitis is a condition that causes pain and swelling inside the scrotum (the sac that holds the testicles).  
It is due to an infection either in the:
•	epididymis – tube carrying the sperm from the testicle to the vas deferens and then the urethra or water pipe (epididymitis)
•	testicle (orchitis)
•	epididymis and testicle (epididymo-orchitis)

In people under 35 the infection is often sexually transmitted e.g. chlamydia or gonorrhoea. Bacteria or viruses transferred into the urethra such as following sex or a surgical procedure can cause epididymo-orchitis, as can non-infectious causes. 
Another condition that causes similar symptoms as epididymo-orchitis in young people is called testicular torsion. This is where the testicle may twist around in the scrotum (ball sack). It causes sudden onset severe pain and swelling and may result in long-term damage to the testicle if not dealt with quickly. 

How common is epididymo-orchitis?
It occurs most commonly in people aged 19–40 years. 

How do you develop epididymo-orchitis?
In people under the age of 35 years the most common cause is a sexually transmitted infection (STI) such as chlamydia or gonorrhoea.
In people over the age of 35 years the most common cause is a urine infection. 
Occasionally it may also be due to a ‘gut’ bacterial infection from penetrative anal sex.
Rarely epididymo-orchitis may be caused by other infections such as mumps or tuberculosis.

What would I notice if I had epididymo-orchitis?
Pain and swelling inside the scrotum (ball sack).  
Some people may also get pain on urination, a discharge from the urethra (water pipe), or feel unwell with a fever. 

How do I get tested for epididymo-orchitis?
If the health professional suspects you have epididymo-orchitis they may examine your penis and scrotum (ball sack), and take urine tests, blood tests and a swab from the urethra (water pipe). We recommend that you have routine tests for sexually transmitted infections including chlamydia, gonorrhoea, syphilis and HIV.
If the clinician assessing you has any concern about a possible torsion of the testicle you will be referred immediately to the emergency department (A&E) or Urology team for further assessment and investigations.

How is epididymo-orchitis treated?
Epididymo-orchitis is usually diagnosed on the day and treatment started. It is easily treated with antibiotics, painkillers and rest but the pain frequently takes weeks to months to completely settle. All treatments at sexual health clinics are free and given to you in the clinic or their linked pharmacy. Supportive underwear or scrotal support (available from online retailers) may help ease the pain and swelling. 
In some patients (e.g. where a bacterial infection is found in the urine or bladder), a diagnosis of epididymo-orchitis may mean that further tests are needed.  
If your symptoms get worse or fail to improve within 3 days you should re-attend the clinic or seek further medical advice.

What about my partners?
If you have been diagnosed with an STI then any sexual partners you have had within the preceding 2-4 weeks need to have a full sexual health screen. Your clinic will advise you further about this.

When can I have sex again? 
As epididymo-orchitis can be caused by sexually transmitted infections It is best that you do not have sexual intercourse until you have completed treatment and your partner has been tested and where applicable, treated. Your clinic will advise you further about this.

What happens if my epididymo-orchitis is left untreated?
Left untreated, epididymo-orchitis can result in 
•	Continued pain and swelling of the testicle
•	Accumulation of fluid around the testicle
•	A collection of pus in the scrotum 
•	Very rarely, shrinkage of the testicle and loss of fertility 
Prompt and early treatment will significantly reduce the likelihood of these complications. 

This leaflet was produced by the Clinical Effectiveness Group of the British Association for Sexual Health and HIV (BASHH). The information in the leaflet is based on the ‘United Kingdom BASHH national guideline for the management of epididymo-orchitis, 2019’ published by BASHH. More information: BASHH: The leaflet was developed following The Information Standard principles developed by NHS England. More information:

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Copyright BASHH 2022. This leaflet was first published 10/2022. Revision date 01/2027.