What is orchitis?
Orchitis is inflammation of the testis (testicle) or testes (testicles).
Orchitis doesn’t often occur alone it’s usually accompanied by inflammation of the epididymis (epididymo-orchitis)1. Epididymo-orchitis is a common cause of pain and swelling in the scrotum.
Two or three out of every 10 men who get mumps develop orchitis1.
Symptoms of orchitis
Orchitis is painful and can be accompanied by swelling and redness. The pain usually comes on quickly3.
Causes of orchitis
Orchitis on its own, without inflammation of the epididymis, is most often caused by viral infection that reaches the testes through the bloodstream3. The mumps virus is the most common of these infections.
Epididymo-orchitis is usually caused by bacterial infections. In adolescent males and young men, sexually transmitted infections (STIs) by the bacteria that cause gonorrhoea or chlamydia are the most common cause. In boys and older men, bacteria that usually cause urinary tract infections are the most common cause3.
Diagnosis of orchitis
Your doctor can diagnose orchitis and epididymo-orchitis by examining you. It’s important to rule out other causes of testicular pain, especially testicular torsion. Your doctor might order an ultrasound scan to rule out testicular torsion.
Your doctor might analyse your urine or order a blood test to work out what type of infection might be causing your orchitis.
Treatment or orchitis
The usual treatment for orchitis is pain relief and rest.
If you have a bacterial infection, your doctor will probably prescribe antibiotics.
Health effects of orchitis
Orchitis can affect the function of the affected testis, so changes in your testosterone levels or sperm production can occur for a while.
If your orchitis (or epididymo-orchitis) is caused by an STI (e.g. chlamydia, gonorrhoea), you should be tested for other possible STIs. Your sexual partner(s) should also be tested.
If your orchitis is caused by mumps, your affected testis (or testes) can become smaller because of damage from the infection and inflammation. There may also be an effect on your fertility. This is why it’s important to be vaccinated against mumps.
What to do about orchitis
See a doctor immediately if you have a sudden onset of pain in your scrotum. If the pain is due to testicular torsion, surgery will be needed straight away.
There’s not much you can do to treat orchitis in many cases, but your doctor can help you find a treatable cause if there is one.
Questions to ask your doctor about orchitis
- How long do you think it will take until I see some improvement?
- Is there any medication that can help treat my orchitis?
- How can I know if my orchitis is caused by a sexually transmitted infection?
- How can I make sure my testosterone levels and fertility haven’t been affected by orchitis?
 Schuppe et al., 2008. Chronic orchitis: a neglected cause of male infertility?. Andrologia 40, 84–91.doi:10.1111/j.1439-0272.2008.00837.x
 Street et al., 2017. The 2016 European guideline on the management of epididymo-orchitis. International Journal of STD & AIDS
 Trojian et al., 2009. Epididymitis and orchitis: an overview. American Family Physician
 Davis et al., 2010. The increasing incidence of mumps orchitis: a comprehensive review. BJU International