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Epididymitis is inflammation of the small coiled tube (epididymis) at the back of the testicle. The result is pain and swelling in the loose bag of skin underneath the penis (scrotum). Epididymitis most commonly affects men between the ages of 19 and 35.

The epididymis connects the testicle with the vas deferens, the tube that carries sperm. In most cases, the cause of the inflammation is a bacterial infection that spreads from your bladder or the tube that drains urine from your bladder (urethra).

For heterosexual men older than 40 and for homosexual men, the most common cause of the infection is a urinary tract infection that spreads to the epididymis. For young heterosexual men, the most common cause is a sexually transmitted disease (STD); for them, the best way to prevent epididymitis is to avoid behaviors that may result in STDs.

The signs and symptoms of epididymitis may include:

• Testicular swelling on one or both sides
• Scrotal pain ranging from mild to severe
• Tenderness in one or both testicles
• Tenderness in the groin, felt in the fold of the skin between your thigh and abdomen
• Painful urination
• Painful intercourse or ejaculation
• Fever
• Discharge from penis
• Blood in the semen

Epididymitis may be acute or chronic.

Acute

• Signs and symptoms usually come on over a day or two.
• They tend to be severe.
• They usually clear up with treatment.

Chronic

• This form may result from several episodes of untreated acute epididymitis.
• If the chronic form occurs on its own, the cause generally is unknown.
• Symptoms tend to come on gradually.
• Treatment may improve symptoms but not clear them up completely.

A number of bacterial organisms can lead to epididymitis. Often the cause of the infection is an STD, particularly gonorrhea, chlamydia or both. Children, older men and homosexual men are more likely to have non-sexually-transmitted forms of the infection.

Urinary tract infections may spread to the epididymis. For men older than 40 who have a history of urinary tract infections or prostate infections, the spread of bacteria from the infected site is the most common cause of epididymitis. In those instances, bacteria may travel up the vas deferens to the epididymis. Other causes may be related to anatomical abnormalities in the urinary tract or having had a catheter or surgical instruments inserted into the penis, which can introduce bacteria into the genital-urinary tract.

High-risk sexual behaviors put you at risk of sexually transmitted epididymitis. They include:

• Multiple sex partners
• Sex with a partner who has an STD
• Sex without a condom
• Personal history of an STD

For older men, having chronic urinary tract infections or prostate infections increases the risk of developing epididymitis. Also, having an enlarged prostate that obstructs bladder function and causes urine to remain in the bladder puts you at higher risk of bladder infections, which increases the risk of epididymitis. Surgery of the urinary tract or having a catheter in place also increases risk.

If you experience pain or swelling in your scrotum, contact your doctor. A number of conditions can cause testicular pain, and some of the conditions require immediate treatment. Your doctor can determine which condition is causing your pain.

Your doctor will conduct a physical exam, which may reveal enlarged lymph nodes in your groin and an enlarged testicle on the affected side, both of which may be tender to the touch. Your doctor also may do a rectal examination to check for prostate enlargement or tenderness and order blood and urine tests to check for infection and other abnormalities.

Other tests your doctor might order include:

• STD screening. This involves obtaining a sample of discharge from your urethra. Your doctor may insert a narrow swab into the end of your penis to obtain the sample, which is then tested for the presence of bacteria or other infectious organisms. The results can be used to select the most effective antibiotic for treatment.
• Ultrasound imaging. Your doctor may use this test, which uses high-frequency sound waves to create precise images of structures inside your body, to ensure there isn't another reason for your symptoms. The main conditions to be ruled out are twisting of the spermatic cord (testicular torsion), which inhibits blood flow to the testes, and testicular tumor. If the ultrasound shows increased blood flow to your testicle, it supports a diagnosis of epididymitis.
• Nuclear scan of the testicles. Also used to rule out testicular torsion, this test involves injecting trace amounts of radioactive material into your bloodstream. Special cameras then can detect areas in your testicles that receive less blood flow, indicating torsion, or more blood flow, supporting the diagnosis of epididymitis.

Epididymitis may eventually cause

• Shrinkage of the affected testicle (atrophy)
• Scrotal abscess, the infected tissue fills with pus
• Chronic epididymitis, which can occur when untreated acute epididymitis leads to recurrent episodes
• Impaired fertility (rare)

If the condition spreads from your epididymis to your testicle, the resulting condition is known as epididymo-orchitis. Signs, symptoms and treatment options are basically the same as they are for epididymitis.

Treatment for epididymitis is with antibiotic medications. Drugs most commonly used to treat epididymitis include ceftriaxone (Ceftin), ciprofloxacin (Cipro), doxycycline (Doryx, Vibramycin), azithromycin (Zithromax), and trimethoprim and sulfamethoxazole combined (Bactrim, Septra). Make sure your doctor is aware of any other medications you're taking or any allergies you have. This information, as well as determining what type of infection you have, will help your doctor select the best treatment.

Be sure to take the entire course of antibiotics prescribed by your doctor, even though you may get relief from your symptoms in two to three days after you start treatment. If you're not feeling better in that time, contact your doctor. When you've finished your medication, it's a good idea to return to your doctor for a follow-up visit to be sure that the infection has cleared up.

Safer sexual practices, such as monogamous sex and condom use, help protect against STDs. If you have recurrent urninary tract infections or other risk factors for epididymitis, your doctor may discuss with you other ways to prevent recurrent episodes of epididymitis.

Having epididymitis usually means you're experiencing considerable pain and discomfort. To ease your symptoms, try these suggestions:

• Rest in bed. Depending on the severity of your discomfort, you may want to stay in bed one or two days.
• Elevate your scrotum. While lying down, place a folded towel under your scrotum.
• Wear an athletic supporter. A supporter provides better support than boxers do for the scrotum.
• Apply cold packs to your scrotum. Wrap the pack in a thin towel and remove the cold pack every 30 minutes or so to avoid damaging your skin.