Epididymitis: Symptoms, Causes & Treatment

What Is Epididymitis?

Epididymitis is an inflammation of the epididymis, the coiled tube behind each testicle that stores and transports sperm. The condition causes pain, swelling, and tenderness in the scrotum, typically on one side. It affects approximately 600,000 men annually in the United States and is most common in men aged 19-35.

The epididymis is a tightly coiled tube approximately 6 meters (20 feet) long when uncoiled, located along the back surface of each testicle. This remarkable structure serves as both a storage facility and maturation site for sperm. After sperm are produced in the testicles, they travel to the epididymis where they spend approximately two to three weeks maturing and gaining the ability to swim and fertilize an egg.

When the epididymis becomes inflamed, usually due to bacterial infection, the resulting condition is called epididymitis. The inflammation can occur on one side (unilateral) or, less commonly, on both sides (bilateral). If the infection spreads to involve the testicle itself, the combined condition is termed epididymo-orchitis, which occurs in approximately 50-60% of epididymitis cases.

Epididymitis can be classified by duration into two main types. Acute epididymitis develops over one to three days and lasts less than six weeks, while chronic epididymitis involves pain or discomfort persisting for six weeks or longer. Chronic cases may develop following inadequately treated acute infections or may have no identifiable infectious cause.

Understanding the Anatomy

To understand epididymitis, it helps to know how the male reproductive system is organized. Each testicle is connected to a complex network of tubes that transport sperm from the site of production to ejaculation. The seminiferous tubules within the testicle produce sperm, which then travel through the efferent ductules into the epididymis.

The epididymis consists of three regions: the head (caput), body (corpus), and tail (cauda). Sperm enter through the head and gradually move through the body to the tail, where they are stored until ejaculation. From the tail, sperm enter the vas deferens, the muscular tube that carries them toward the urethra during ejaculation.

This anatomical arrangement explains why infections can reach the epididymis. Bacteria typically travel backward (retrograde) from the urethra, through the vas deferens, and into the epididymis. This ascending route of infection is the most common pathway for bacterial epididymitis.

What Causes Epididymitis?

Epididymitis is most commonly caused by bacterial infections. In sexually active men under 35, sexually transmitted infections (STIs) like Chlamydia trachomatis and Neisseria gonorrhoeae are responsible for most cases. In older men, urinary tract bacteria such as E. coli are more common causes. Non-infectious causes include certain medications, trauma, and autoimmune conditions.

The causes of epididymitis vary significantly based on age and sexual activity, making accurate diagnosis essential for appropriate treatment. Understanding these differences helps healthcare providers select the correct antibiotics and determine whether partner notification is necessary.

Sexually Transmitted Infections

In sexually active men under age 35, sexually transmitted infections account for approximately 50-65% of epididymitis cases. Chlamydia trachomatis is the most common causative organism in this age group, responsible for roughly 40% of cases. Chlamydia infections are often asymptomatic in the urethra, allowing the infection to ascend to the epididymis before symptoms develop.

Neisseria gonorrhoeae (gonorrhea) is the second most common sexually transmitted cause, responsible for approximately 20% of cases in young men. Gonorrhea typically causes more acute symptoms than chlamydia, including urethral discharge and painful urination, though it can also be asymptomatic.

Other sexually transmitted organisms that can cause epididymitis include Mycoplasma genitalium, an emerging pathogen increasingly recognized as a cause of male urogenital infections, and Ureaplasma urealyticum, though the role of these organisms is less well-established.

Non-Sexually Transmitted Bacterial Infections

In men over age 35, children, and men who have sex with men practicing insertive anal intercourse, enteric (gut) bacteria are the most common cause. Escherichia coli (E. coli) is the predominant organism, responsible for approximately 60-80% of non-STI cases.

Other enteric bacteria that can cause epididymitis include Pseudomonas aeruginosa, Klebsiella species, and Proteus species. These organisms typically reach the epididymis through the urinary tract, ascending from the bladder through the vas deferens.

Conditions that increase the risk of urinary tract infections also increase epididymitis risk. These include benign prostatic hyperplasia (BPH), which causes urinary retention and incomplete bladder emptying; urethral strictures, which slow urine flow; and neurogenic bladder, which affects bladder function.

Other Causes and Risk Factors

Several non-infectious factors can cause or contribute to epididymitis. Urological procedures such as catheterization, cystoscopy, transurethral resection of the prostate (TURP), and vasectomy can introduce bacteria or cause inflammation leading to epididymitis.

Certain medications have been associated with epididymitis, most notably amiodarone, an anti-arrhythmic drug. Amiodarone and its metabolites accumulate in the epididymis, causing a non-bacterial inflammatory response. This typically resolves when the medication is stopped or the dose is reduced.

Trauma to the scrotum can cause epididymal inflammation, as can strenuous physical activity or heavy lifting that increases intra-abdominal pressure. Tuberculosis is an important cause of epididymitis in endemic areas and should be considered in patients with risk factors or who fail to respond to standard antibiotic therapy.

In children, epididymitis is relatively uncommon and often has different causes than in adults. Viral infections, particularly mumps, can cause epididymitis or orchitis. Anatomical abnormalities such as ectopic ureter or posterior urethral valves may predispose to recurrent infections.

What Are the Symptoms of Epididymitis?

The main symptoms of epididymitis include gradual onset of testicular pain (usually one-sided), scrotal swelling, tenderness when touching the epididymis, and fever. Pain may radiate to the lower abdomen or groin. Urinary symptoms such as painful urination and frequency are common. Urethral discharge suggests a sexually transmitted cause.

Epididymitis symptoms typically develop gradually over one to three days, which helps distinguish it from testicular torsion (which causes sudden, severe pain). The symptoms can range from mild discomfort to severe pain requiring emergency care.

Scrotal and Testicular Symptoms

The hallmark symptom of epididymitis is scrotal pain, typically localized to one side and often described as a dull ache that progressively worsens. Initially, the pain may be limited to the back of the testicle where the epididymis is located, but it often spreads to involve the entire testicle and scrotum as the condition progresses.

Scrotal swelling develops as inflammation increases, and the affected side may appear visibly larger than the unaffected side. The scrotum may become red and warm to the touch, reflecting the underlying inflammatory process. In severe cases, the swelling can be substantial and may obscure the normal anatomy.

On physical examination, the epididymis is tender and may feel enlarged and indurated (hardened). Early in the disease, the epididymis can be distinguished from the testicle, but as inflammation progresses and the testicle becomes involved, this distinction becomes difficult.

A characteristic finding is the positive Prehn sign: elevating the scrotum (such as by placing a rolled towel beneath it while lying down) provides some relief of pain in epididymitis. This occurs because elevation reduces tension on the inflamed structures. In contrast, elevation does not relieve pain in testicular torsion.

Urinary Symptoms

Because epididymitis often results from ascending infection through the urinary tract, urinary symptoms are common. Dysuria (painful or burning urination) occurs in approximately 30-50% of patients and may precede scrotal symptoms.

Urinary frequency and urgency reflect irritation of the bladder or urethra by infection. Some patients notice urethral discharge, which is particularly suggestive of sexually transmitted infection. The discharge may be clear, white, or yellow-green depending on the causative organism.

Hematuria (blood in urine) or hematospermia (blood in semen) may occur, reflecting inflammation of the genital tract. These symptoms, while alarming, usually resolve with treatment of the underlying infection.

Systemic Symptoms

Fever occurs in approximately 20-40% of patients with acute bacterial epididymitis. High fever (above 38.5°C or 101.3°F) is more common with severe infections and may indicate developing complications. Chills, malaise, and body aches may accompany fever.

Some patients experience lower abdominal or flank pain, which may reflect involvement of the spermatic cord or prostatic inflammation. Pain may radiate to the groin, inner thigh, or lower back.

When Should You See a Doctor?

See a doctor promptly if you have testicular pain or scrotal swelling, especially with fever. Seek emergency care immediately for sudden, severe testicular pain (to rule out testicular torsion, which requires surgery within 6 hours), high fever with severe scrotal swelling, or inability to urinate. Early treatment prevents complications.

While epididymitis is generally not life-threatening, prompt medical evaluation is important for several reasons. First, testicular pain requires evaluation to exclude testicular torsion, a surgical emergency. Second, delayed treatment of epididymitis increases the risk of complications including abscess formation and chronic pain. Third, if an STI is the cause, early diagnosis enables treatment of sexual partners and prevents further transmission.

Differentiating Epididymitis from Testicular Torsion

One of the most critical aspects of evaluating scrotal pain is distinguishing epididymitis from testicular torsion. Torsion occurs when the testicle rotates on its blood supply, cutting off circulation. Without emergency surgery within approximately 6 hours, the testicle may be permanently damaged or lost.

Several features help differentiate these conditions. Epididymitis typically develops gradually over hours to days, while torsion causes sudden, severe pain that often wakes patients from sleep or occurs during physical activity. In epididymitis, the epididymis is predominantly tender and swollen, while in torsion, the entire testicle is exquisitely tender.

The Prehn sign (relief of pain with scrotal elevation) is classically positive in epididymitis and negative in torsion, though this finding is not completely reliable. The cremasteric reflex (contraction of the cremaster muscle when the inner thigh is stroked) is typically absent in torsion but present in epididymitis.

Patients with epididymitis often have urinary symptoms (painful urination, frequency, discharge), while these are typically absent in torsion. Fever is more common with epididymitis. However, because clinical examination alone cannot definitively exclude torsion, imaging studies (particularly scrotal ultrasound with Doppler flow) are often performed.

How Is Epididymitis Diagnosed?

Epididymitis is diagnosed through physical examination, urine tests (urinalysis and culture), and STI testing (nucleic acid amplification tests for chlamydia and gonorrhea). Scrotal ultrasound with Doppler evaluates blood flow to rule out testicular torsion and may show an enlarged, inflamed epididymis. Blood tests assess infection severity.

Accurate diagnosis of epididymitis involves confirming the diagnosis, identifying the causative organism to guide antibiotic selection, and excluding other serious conditions, particularly testicular torsion.

Physical Examination

The examination begins with inspection and palpation of the scrotum. In epididymitis, the epididymis (located along the posterior aspect of the testicle) is swollen, warm, and tender. Early in the disease, the epididymis may be distinguishable from the testicle, but as inflammation progresses, the structures become indistinguishable.

The spermatic cord may be thickened and tender if the infection has spread proximally. The presence of a hydrocele (fluid accumulation around the testicle) suggests a reactive inflammatory process. Examination of the prostate may reveal tenderness or enlargement.

Laboratory Testing

Urinalysis typically shows pyuria (white blood cells in urine) and may show bacteriuria. Urine culture identifies the causative organism in many cases, particularly when enteric bacteria are responsible.

Nucleic acid amplification tests (NAATs) are the preferred method for detecting chlamydia and gonorrhea. These highly sensitive tests can be performed on urine samples or urethral swabs. First-void urine (the first portion of the urine stream) provides the highest yield for STI detection.

If urethral discharge is present, a Gram stain can provide rapid preliminary information. The presence of gram-negative intracellular diplococci suggests gonorrhea, while increased white blood cells without visible organisms may indicate chlamydial infection.

Blood tests including complete blood count (showing elevated white cell count) and inflammatory markers (C-reactive protein, erythrocyte sedimentation rate) help assess infection severity but are not specific for epididymitis.

Imaging Studies

Scrotal ultrasound with color Doppler is the imaging study of choice for evaluating scrotal pain. In epididymitis, ultrasound typically shows an enlarged, hypoechoic (darker) epididymis with increased blood flow on Doppler examination, reflecting the inflammatory hyperemia.

Critically, Doppler ultrasound can assess testicular blood flow to exclude torsion, where blood flow would be reduced or absent. Ultrasound can also identify complications such as abscess formation, testicular involvement (epididymo-orchitis), or alternative diagnoses like testicular tumor or hydrocele.

How Is Epididymitis Treated?

Epididymitis is treated with antibiotics for 10-14 days. For STI-related cases, a single injection of ceftriaxone plus doxycycline (100mg twice daily for 10 days) is standard. For non-STI cases, fluoroquinolones like levofloxacin are used. Supportive care includes rest, scrotal elevation, ice packs, and NSAIDs for pain. Sexual partners need treatment if an STI is the cause.

Effective treatment of epididymitis requires appropriate antibiotics targeting the likely causative organisms, supportive measures to relieve symptoms, and follow-up to ensure resolution. Partner notification and treatment are essential when a sexually transmitted infection is identified.

Antibiotic Treatment

Antibiotic selection depends on the most likely causative organism, which varies by age, sexual history, and risk factors. Treatment is typically started empirically (based on clinical judgment) before culture results are available, then adjusted if needed based on test results.

For sexually active men under 35 or men with STI risk factors, treatment targets both chlamydia and gonorrhea:

• Ceftriaxone 500mg intramuscularly (single dose) – covers gonorrhea
• Plus doxycycline 100mg orally twice daily for 10 days – covers chlamydia

For men over 35 without STI risk factors, or when enteric bacteria are suspected:

• Levofloxacin 500mg orally once daily for 10 days, or
• Ofloxacin 300mg orally twice daily for 10 days

For men who practice insertive anal intercourse, both STI coverage and enteric bacteria coverage may be needed, combining ceftriaxone plus doxycycline with a fluoroquinolone.

It is essential to complete the entire antibiotic course even if symptoms improve, which they typically do within 48-72 hours. Stopping antibiotics early can lead to treatment failure, recurrence, and the development of antibiotic-resistant bacteria.

Supportive Care

Several self-care measures help relieve symptoms and promote healing:

• Bed rest during the acute phase helps reduce inflammation and discomfort
• Scrotal elevation using supportive underwear (briefs rather than boxers) or a rolled towel while lying down reduces swelling and pain
• Cold compresses applied to the scrotum (wrapped in cloth, not directly on skin) for 15-20 minutes several times daily reduce swelling
• NSAIDs such as ibuprofen (400-600mg every 6-8 hours) or naproxen reduce pain and inflammation
• Avoid strenuous activity and heavy lifting for at least 2-4 weeks
• Stay hydrated and urinate regularly to help clear urinary tract bacteria

Partner Notification and Treatment

When epididymitis is caused by a sexually transmitted infection, all sexual partners from the past 60 days should be notified and evaluated for STIs. Partners should be treated presumptively (even without symptoms) because many STIs are asymptomatic.

This partner notification serves two purposes: it prevents reinfection of the treated patient (ping-pong transmission), and it stops further spread of the STI in the community. Many health departments offer partner notification services that maintain patient confidentiality.

What Are the Possible Complications?

Untreated or inadequately treated epididymitis can lead to several complications including abscess formation (requiring surgical drainage), chronic epididymitis (persistent pain beyond 6 weeks), spread of infection to the testicle (epididymo-orchitis), infertility due to epididymal scarring, and rarely, Fournier's gangrene (necrotizing fasciitis of the scrotum).

Most cases of epididymitis resolve completely with appropriate treatment. However, delayed treatment, inadequate antibiotic courses, or particularly virulent infections can lead to complications that may require additional intervention or cause lasting effects.

Abscess Formation

An epididymal or scrotal abscess occurs when infection localizes into a walled-off collection of pus. This complication is suggested by persistent or worsening symptoms despite antibiotic treatment, fluctuant (soft, compressible) swelling on examination, and characteristic findings on ultrasound.

Small abscesses may respond to prolonged antibiotic therapy, but larger collections typically require surgical drainage. In severe cases, orchiectomy (removal of the testicle) may be necessary if the testicle is extensively damaged or the infection cannot otherwise be controlled.

Chronic Epididymitis

Chronic epididymitis is defined as pain or discomfort persisting for six weeks or longer. This occurs in approximately 15% of patients following acute epididymitis. The pain is often less severe than during the acute episode but can significantly impact quality of life.

Treatment of chronic epididymitis is challenging. Options include prolonged antibiotic courses (if bacterial persistence is suspected), anti-inflammatory medications, nerve blocks, and in refractory cases, surgical epididymectomy (removal of the epididymis).

Impact on Fertility

Epididymitis can affect fertility through several mechanisms. Inflammation may damage the delicate epididymal tubules, leading to scarring and obstruction that blocks sperm passage. The inflammatory process may also directly damage sperm or impair their maturation.

Bilateral epididymitis (affecting both sides) poses the greatest fertility risk, potentially causing obstructive azoospermia (absence of sperm in semen due to blockage). Even unilateral disease can affect sperm quality on the affected side.

Men concerned about fertility after epididymitis should wait at least 3 months after resolution (the time for new sperm to be produced and mature) before having a semen analysis to assess sperm count and quality.

How Can You Prevent Epididymitis?

Prevent epididymitis by practicing safe sex (using condoms consistently), getting tested for STIs with new partners, treating urinary tract infections promptly, and staying well-hydrated. Men undergoing urological procedures should receive appropriate antibiotic prophylaxis. Avoid heavy lifting during recovery from any genital tract infection.

Because the causes of epididymitis differ by age and risk factors, prevention strategies vary accordingly. For sexually active young men, STI prevention is key, while older men benefit more from urinary tract infection prevention.

Preventing STI-Related Epididymitis

Since sexually transmitted infections are the leading cause of epididymitis in young men, safe sex practices are the most effective prevention:

• Consistent condom use significantly reduces the risk of chlamydia, gonorrhea, and other STIs
• Limiting number of sexual partners reduces overall STI exposure
• Regular STI screening allows early detection and treatment before complications develop
• Partner communication about STI status and testing helps make informed decisions
• Prompt treatment of any diagnosed STI prevents progression to epididymitis

Preventing Non-STI Epididymitis

For urinary tract-related causes, general urinary health measures help:

• Stay well hydrated to maintain good urine flow and reduce bacterial concentration
• Urinate regularly and completely; don't ignore the urge to urinate
• Treat urinary tract infections promptly before they can ascend to the epididymis
• Manage prostate conditions that cause urinary retention or incomplete emptying
• Follow sterile technique for any urological procedures

What Is the Outlook for Epididymitis?

The prognosis for epididymitis is generally excellent with appropriate antibiotic treatment. Most patients experience symptom improvement within 48-72 hours, though complete resolution takes 4-6 weeks. About 85% recover without long-term complications. Chronic pain develops in approximately 15% of cases. Fertility is usually preserved with prompt treatment.

The vast majority of men with acute epididymitis make a full recovery when treated appropriately. Understanding the expected timeline helps patients know when their recovery is progressing normally and when to seek additional care.

Within 48-72 hours of starting antibiotics, most patients notice significant improvement in pain and fever. Swelling typically takes longer to resolve, often persisting for several weeks even as other symptoms improve.

Complete resolution usually occurs within 4-6 weeks, though some patients notice residual firmness or mild tenderness of the epididymis for several months. This gradual resolution is normal and does not indicate treatment failure.

Patients should return for follow-up if symptoms do not improve within 48-72 hours, worsen at any point, or fail to resolve within the expected timeframe. These situations may indicate antibiotic resistance, abscess formation, or an alternative diagnosis.