Orchitis is swelling (inflammation) of one or both of the testicles.
Epididymo - orchitis; Testis infection
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. Mumps is now rare in the United States due to childhood vaccinations.
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:
High-risk sexual behaviors
Multiple sexual partners
Personal history of gonorrhea or another STI
Sexual partner with a diagnosed STI
Risk factors for orchitis not due to an STI include:
Acute pain in the scrotum or testicles can be caused by twisting of the testicular blood vessels (torsion). This is a medical emergency that requires immediate surgery.
A swollen testicle with little or no pain may be a sign of testicular cancer. If this is the case, you should have a testicular ultrasound.
When to Contact a Medical Professional
See your health care provider for an exam if you have testicle problems.
Get emergency medical help if you have sudden pain in the testicle.
Things you can do to prevent the problem include:
Get vaccinated against mumps.
Practice safer sex behaviors to decrease your risk of STIs.
Mason WH. Mumps. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 240.
McGowan CC, Krieger J. Prostatitis, epididymitis, and orchitis. In: Bennett JE, ed . Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2015:chap 112.
Nickel JC. Prostatitis and related conditions, orchitis, and epididymitis. In: Wein AJ, ed. Campbell-Walsh Urology. 10th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 11.
Scott Miller, MD, urologist in private practice in Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.