Symptoms and causes

What is it?

A testicular infection or orchitis is an inflammation of the testicles. The condition usually has sudden onset and causes pain and swelling on one side of the scrotum.

When a bacterial inflammation of the epididymis is severe, over time the testicle itself becomes involved in the process: this is called ‘epididymo orchitis’. Sometimes, the condition becomes chronic.

Some types of orchitis do not originate from an epididymitis: the most common type is mumps-related orchitis. The testicular inflammation occurs shortly after contracting mumps in adulthood: first, the salivary gland becomes inflamed, then the testicular infection arises a few days to weeks later. This can even occur in men who were vaccinated against mumps in their youth.

Less frequent forms of orchitis include: syphilis, tuberculosis, brucellosis and cryptococcus.

Diagnosis and treatment


  • Clinical examination
  • Ultrasound imaging


The most common cause of testicular inflammation is the mumps virus; consequently, antibiotics are not part of the treatment. Antibiotics only affect bacteria, not viruses. Orchitis caused by the mumps virus cannot be resolved, it can only be treated ‘symptomatically’ with painkillers, anti-inflammatory drugs and possibly ice application and (bed) rest.

Treatment centres and specialisations

Urology Centre

Latest publication date: 25/01/2021
Supervising author: Dr Ameye Filip