Orchitis (or-KIE-tis) is an inflammation of one or both testicles. Bacterial or viral infections can cause orchitis, or the cause can be unknown. Orchitis is most often the result of a bacterial infection, such as a sexually transmitted infection (STI). In some cases, the mumps virus can cause orchitis.
Bacterial orchitis might be associated with epididymitis — an inflammation of the coiled tube (epididymis) at the back of the testicle that stores and carries sperm. In that case, it's called epididymo-orchitis.
Orchitis causes pain and can affect fertility. Medication can treat the causes of bacterial orchitis and can ease some signs and symptoms of viral orchitis. But it can take several weeks for scrotal tenderness to disappear.
Orchitis signs and symptoms usually develop suddenly and can include:
- Swelling in one or both testicles
- Pain ranging from mild to severe
- Nausea and vomiting
- General feeling of unwellness (malaise)
The terms "testicle pain" and "groin pain" are sometimes used interchangeably. But groin pain occurs in the fold of skin between the thigh and abdomen — not in the testicle. The causes of groin pain are different from the causes of testicle pain.
When to see a doctor
If you have pain or swelling in your scrotum, especially if the pain occurs suddenly, see your doctor right away.
A number of conditions can cause testicle pain, and some require immediate treatment. One such condition involves twisting of the spermatic cord (testicular torsion), which might cause pain similar to that caused by orchitis. Your doctor can perform tests to determine which condition is causing your pain.
Orchitis can be caused by a bacterial or viral infection. Sometimes a cause of orchitis can't be determined.
Most often, bacterial orchitis is associated with or the result of epididymitis. Epididymitis usually is caused by an infection of the urethra or bladder that spreads to the epididymis.
Often, the cause of the infection is an STI. Other causes of infection can be related to having been born with abnormalities in your urinary tract or having had a catheter or medical instruments inserted into your penis.
The mumps virus usually causes viral orchitis. Nearly one-third of males who contract the mumps after puberty develop orchitis, usually four to seven days after onset of the mumps.
Risk factors for nonsexually transmitted orchitis include:
- Not being immunized against mumps
- Having recurring urinary tract infections
- Having surgery that involves the genitals or urinary tract
- Being born with an abnormality in the urinary tract
Sexual behaviors that can lead to STIs put you at risk of sexually transmitted orchitis. Those behaviors include having:
- Multiple sexual partners
- Sex with a partner who has an STI
- Sex without a condom
- A personal history of an STI
Complications of orchitis may include:
- Testicular atrophy. Orchitis can eventually cause the affected testicle to shrink.
- Scrotal abscess. The infected tissue fills with pus.
- Infertility. Occasionally, orchitis can cause infertility or inadequate testosterone production (hypogonadism). But these are less likely if orchitis affects only one testicle.
To prevent orchitis:
- Get immunized against mumps, the most common cause of viral orchitis
- Practice safe sex, to help protect against STIs that can cause bacterial orchitis