Epididymitis is a medical condition characterized by inflammation of the epididymis, a curved structure at the back of the testicle.

[1] In older males and men who practice insertive anal sex, enteric bacteria are a common cause.

[2] The acute form usually develops over several days, with pain and swelling frequently in only one testis, which will hang low in the scrotum.

Chronic epididymitis can lead to permanent damage or even destruction of the epididymis and testicle (resulting in infertility and/or hypogonadism), and infection may spread to any other organ or system of the body.

[7] In sexually active men, Chlamydia trachomatis is responsible for two-thirds of acute cases, followed by Neisseria gonorrhoeae and E. coli (or other bacteria that cause urinary tract infection).

Particularly among men over age 35 in whom the cause is E. coli, epididymitis is commonly due to urinary tract obstruction.

[3][8] Less common microbes include Ureaplasma, Mycobacterium, and cytomegalovirus, or Cryptococcus in patients with HIV infection.

Rare non-infectious causes of chronic epididymitis include sarcoidosis (more prevalent in black men) and Behçet's disease.

The cremasteric reflex (elevation of the testicle in response to stroking the upper inner thigh) remains normal.

Today, Doppler ultrasound is a common test: it can demonstrate areas of blood flow and can distinguish clearly between epididymitis and torsion.

These may include microscopy and culture of a first void urine sample, Gram stain and culture of fluid or a swab from the urethra, nucleic acid amplification tests (to amplify and detect microbial DNA or other nucleic acids) or tests for syphilis and HIV.

Chronic epididymitis is most commonly associated with lower back pain, and the onset of pain often co-occurs with activity that stresses the low back (i.e., heavy lifting, long periods of car driving, poor posture while sitting, or any other activity that interferes with the normal curve of the lumbar lordosis region).

In chronic epididymitis, a four- to six-week course of antibiotics may be prescribed to ensure the complete eradication of any possible bacterial cause, especially the various chlamydiae.

Surgical removal of the epididymis is rarely necessary, causes sterility, and only gives relief from pain in approximately 50% of cases.

It is generally believed that most cases of chronic epididymitis will eventually "burn out" of the patient's system if left untreated, though this might take years or even decades.

[16] Epididymitis makes up 1 in 144 visits for medical care (0.69 percent) in men 18 to 50 years old or 600,000 cases in males between 18 and 35 in the United States.