What Is It, Symptoms, Causes, Diagnosis, Treatment, and More

Author:Lahav Constantini

Editors:Antonella Melani, MD,Lisa Miklush, PhD, RN, CNS,Ahaana Singh

Illustrator:Abbey Richard

What is epididymitis?

Epididymitis refers to the inflammation of the epididymis, which is a coiled tube in the back of the testicle that transports and stores sperm. It carries sperm from the testes to the vas deferens, which then transports sperm to the ejaculatory ducts

If there’s a sudden onset of inflammation that lasts less than six weeks, epididymitis is considered acute. Chronic epididymitis, on the other hand, lasts more than six weeks. Individuals of any age can be affected, but the majority of cases occur for adults between 20–59 years old.

What causes epididymitis?

The most common causes of epididymitis are bacterial infections. Most often, the infection begins in the urethra, bladder, or prostate, and can reach the epididymis through retrograde spread. Other, less frequent, spreading routes include the bloodstream or the lymphatic system.

In children, the infectious pathogen is typically Escherichia coli (E. coli), a species of opportunistic bacteria which normally colonizes the intestines, but can also cause urinary tract infections

For adults under 35 years of age, the most common causes include paramyxoviruses like the mumps virus and sexually transmitted disease (STDs) like gonorrhea and chlamydia, respectively caused by the bacteria Neisseria gonorrhoeae and Chlamydia trachomatis. This is why sexually active adults are at an increased risk for epididymitis, especially those practicing anal intercouse. Individuals with obstruction or congenital abnormalities of the urinary tract are also at increased risk. Other non-infectious causes of epididymitis include trauma, vasculitis (inflammation of blood vessels), medications (such as amiodarone), and autoimmune diseases. Finally, a portion of cases are idiopathic, meaning there is an unknown cause. 

In adults over 35 years old, the most important causes of epididymitis include E. coli and Pseudomonas aeruginosa, as well as genitourinary tuberculosis.

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What does epididymitis feel like?

Epididymitis’ symptoms can come on suddenly or gradually, and include redness, swelling, and pain in the scrotum that can radiate to the lower abdomen. Some cases of epididymitis occur concomitantly with inflammation of the testicles; this is referred to as epididymo-orchitis. If epididymitis is a result of a sexually transmitted disease, it can be preceded by genital skin lesions and urethral discharge. Other lower urinary tract symptoms can also occur, such as difficult or painful urination (dysuria), as well as changes to urinary frequency and urgency. Additionally, people with severe systemic infections may experience nausea, fever, and chills.

Is epididymitis contagious? Is epididymitis an STD?

Epididymitis is not considered a sexually transmitted disease; however, it can often be caused by sexually transmitted infections such as gonorrhea and chlamydia. These bacteria are contagious and can be transmitted from an infected individual to their sex partner through sexual activity or the exchange of body fluids. These infections can then lead to epididymitis in the male reproductive systems.

How is epididymitis diagnosed?

Diagnosis of acute or chronic epididymitis is done through careful clinical examination consisting of a medical and sexual history review, as well as assessment of signs and symptoms. Further assessment involves examination of the testes and scrotum, STD screenings, urine and blood tests, and ultrasound imaging. An important differential diagnosis is testicular torsion (twisting), which requires emergency surgical intervention. In uncertain cases, surgery may be performed to further explore the area and rule out testicular torsion.

How is epididymitis treated?

Pain and discomfort associated with epididymitis are managed by rest, elevation of the scrotum, cold packs, and non-steroidal anti-inflammatory drugs (NSAIDs). Additionally, infectious cases of epididymitis can be treated with antibiotics. If epididymitis is caused by sexually transmitted disease, the physician may recommend that the individual’s sex partner also undergo antibiotic treatment. On the other hand, non-infectious cases of epididymitis need treatment for their underlying cause, or the withdrawal of any causative medication.

Though most people can be treated from home, hospitalization may be considered for severe cases, systemic infections, or individuals with additional diseases (such as diabetes or immunosuppression). Surgery for treatment of epididymitis is not recommended, due to its high failure rate and potential risk of infertility.

What is the best antibiotic to treat epididymitis?

If bacterial infection is suspected, antibiotics are commonly used for disease control and prevention, and to prevent further transmission and complications. The type and duration of antibiotic treatment depends on the individual’s age, sexual activity, signs and symptoms, and medical history. If bacterial cultures are available, they are also taken into consideration. Commonly prescribed antibiotics—which can be used alone or in combination—include quinolones, doxycycline, and ceftriaxone.

What can happen if epididymitis is left untreated?

Untreated cases of acute epididymitis may progress into chronic epididymitis, and potentially lead to chronic pain and additional complications. Some individuals may develop a hydrocele, which is an accumulation of fluid around the testicle that may cause it to appear tender and enlarged. Fistulas, which are abnormal connections between two hollow organs, or swollen lumps filled with pus called abscesses may also appear in others. Epididymitis can also lead to obstruction of blood flow to the testicle, causing further testicular damage and necrosis. If both testicles are affected, epididymitis and its complications may result in infertility.

What are the most important facts to know about epididymitis?

Epididymitis is an inflammatory condition of the epididymis, and can be acute or chronic. Epididymitis can be infectious—caused by intestinal bacteria or sexually transmitted infections, or noninfectious—occurring due to trauma or certain diseases or medications. Symptoms can include pain, swelling, redness in the scrotum, and urinary problems. Diagnosis is done by careful examination, taking into consideration age, history, symptoms, urine and blood tests, and ultrasound imaging. Treatment is based on the underlying cause, usually involving rest, elevation of the scrotum, and analgesics. Additionally, infectious cases should be treated with antibiotics for disease control and prevention, as this reduces the rate of transmission and complications.

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Related links

Mumps virus
Clinical Reasoning: Sexually transmitted infections
Neisseria gonorrhoeae

Resources for research and reference

Abbas, A. K., Aster, J. C., Perkins, J. A., Robbins, S. L., & Kumar, V. (2018). Robbins Basic Pathology (10 edition). Philadelphia, Pennsylvania: Elsevier.

Brewster, S., Cranston, D., Noble, J., & Reynard, J. (2001). Urology: A Handbook for Medical Students. Oxford: BIOS Scientific.

Epididymitis. (2015). CDC. Retrieved September 11, 2020, from

Lynch, S. (2018). Acute epididymitis. Journal of the American Academy of Physician Assistants, 31(3): 50–51. DOI: 10.1097/01.JAA.0000530304.69021.4b

Tracy, C. R. Steers, W. D., and Costabile, R. (2008). Diagnosis and Management of Epididymitis. Urologic Clinics of North America, 35(1): 101–108. DOI: 10.1016/j.ucl.2007.09.013