orchitis causes
Orchitis can be caused by a bacterial or viral infection. Sometimes a cause of orchitis can't be determined (idiopathic orchitis). Most often, bacterial orchitis is 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.
Orchitis may be caused by an infection. Many types of bacteria and viruses can cause this condition. The most common virus that causes orchitis is mumps. It most often occurs in boys after puberty. Orchitis most often develops 4 to 6 days after the mumps begins. Orchitis may also occur along with infections of the prostate or epididymis. Orchitis may be caused by a sexually transmitted infection (STI), such as gonorrhea or chlamydia. The rate of sexually transmitted orchitis or epididymitis is higher in men ages 19 to 35. Risk factors for sexually transmitted orchitis include: 1  High-risk sexual behaviors. 2  Multiple sexual partners. 3  Personal history of gonorrhea or another STI. 4  Sexual partner with a diagnosed STI.