Orchitis is swelling (inflammation) of one or both of the testicles.
Epididymo-orchitis; Testis infection
Causes, incidence, and risk factors
Orchitis may be caused by an infection from many different types of bacteria and viruses.
The most common virus that causes orchitis is mumps. It most often occurs in boys after puberty. Orchitis usually develops 4 - 6 days after the mumps begins. Because of childhood vaccinations, mumps is now rare in the United States.
Orchitis may also occur along with infections of the prostate or epididymis.
Orchitis may be caused by sexually transmitted diseases (STD), such as gonorrhea or chlamydia. The rate of sexually transmitted orchitis or epididymitis is higher in men ages 19 - 35.
Risk factors for sexually transmitted orchitis include:
High-risk sexual behaviors
Multiple sexual partners
Personal history of gonorrhea or another STD
Sexual partner with a diagnosed STD
Risk factors for orchitis not due to an STD include:
Acute pain in the scrotum or testicles can be caused by twisting of the testicular blood vessels (torsion), which is a surgical emergency. If you have sudden pain in the scrotum or testicles, get immediate medical attention.
Calling your health care provider
All testicle abnormalities should be medically evaluated. Call the local emergency number (such as 911) or go to the nearest emergency room if you experience sudden pain in the testicle.
Getting vaccinated against mumps will prevent mumps-associated orchitis. Safer sex behaviors, such as having only one partner at a time (monogamy) and condom use, will decrease the chance of developing orchitis as a result of a sexually transmitted disease.
Krieger JN. Prostatitis, epididymitis, and orchitis. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone;2009:chap 109.
MacDonald NE. Epididymitis, orchitis, and prostatitis. in: Long SS, ed. Principles and Practice of Pediatric Infectious Diseases. 3rd ed. Philadelphia, Pa: Elsevier Churchill Livingstone;2008:chap 57.
Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; and Scott Miller, MD, Urologist in private practice in Atlanta, Georgia. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.