Swollen Scrotum: Causes, Symptoms & When to Seek Care

What Causes a Swollen Scrotum?

The most common causes of swollen scrotum are hydrocele (fluid around the testicle), inguinal hernia extending into the scrotum, varicocele (enlarged veins), and epididymal cyst. Less common causes include epididymitis, orchitis, and rarely testicular cancer. Each cause has distinct characteristics and requires different management approaches.

Scrotal swelling is a relatively common condition that can affect males of any age, from newborns to elderly men. Understanding the underlying cause is essential because while most causes are benign, some require urgent intervention. The scrotum is the pouch of skin that contains the testicles, epididymis, and portions of the spermatic cords. Swelling can originate from any of these structures or from fluid accumulation in the surrounding tissues.

The anatomy of the scrotum makes it susceptible to various conditions. The testicles descend from the abdomen during fetal development, creating a potential pathway for hernia formation. The venous drainage system, particularly on the left side, can become dilated leading to varicocele. Additionally, the spaces around the testicles can fill with fluid, causing hydrocele. Understanding these anatomical factors helps explain why certain conditions occur and guides appropriate treatment.

When evaluating scrotal swelling, doctors consider several factors: whether the swelling is painful or painless, whether it appeared suddenly or gradually, whether it is present on one side or both, and whether it changes with body position or straining. These characteristics help distinguish between different causes and determine the urgency of treatment.

Hydrocele - Fluid Around the Testicle

Hydrocele is one of the most common causes of scrotal swelling, occurring when fluid accumulates in the thin sheath surrounding the testicle called the tunica vaginalis. This condition affects approximately 1-2% of adult men and is particularly common in newborns, where it often resolves spontaneously within the first year of life. In adults, hydrocele typically develops gradually and causes painless swelling that may increase throughout the day.

The fluid collection in hydrocele is usually clear and straw-colored. A characteristic feature is that the swelling transmits light when a flashlight is held against it in a dark room, a test called transillumination. This distinguishes hydrocele from solid masses, which do not transmit light. Most hydroceles are idiopathic, meaning no specific cause is identified, but they can also develop following trauma, infection, or as a complication of inguinal surgery.

In children, hydrocele often occurs because the processus vaginalis, the channel through which the testicle descends, fails to close completely. This communicating hydrocele may fluctuate in size, becoming larger when the child is active and smaller after rest. Adult hydroceles are typically non-communicating, meaning they do not connect to the abdominal cavity and maintain a relatively stable size.

Inguinal Hernia Extending to the Scrotum

An inguinal hernia occurs when abdominal contents, usually intestine or fatty tissue, protrude through a weakness in the abdominal wall at the inguinal canal. When the hernia extends down into the scrotum, it is called an inguinoscrotal hernia. Unlike hydrocele, which develops gradually, hernias may appear suddenly with straining, coughing, or lifting heavy objects.

Inguinal hernias require surgical repair because they do not resolve spontaneously and carry a risk of incarceration or strangulation. Incarceration occurs when the hernia contents become trapped and cannot be pushed back into the abdomen. Strangulation is a medical emergency where the blood supply to the trapped tissue is compromised, requiring immediate surgery to prevent tissue death.

The symptoms of inguinal hernia include a bulge in the groin or scrotum that may be more noticeable when standing or straining, aching or burning sensation at the bulge, and discomfort that worsens with activity. A distinctive feature is that the swelling often reduces or disappears when lying down and increases when standing or bearing down. Pain relief can be achieved with over-the-counter pain medication while awaiting surgery, and a supportive undergarment (athletic supporter or suspensory) can provide comfort.

Varicocele - Enlarged Veins

Varicocele is an enlargement of the veins within the scrotum, similar to varicose veins in the legs. It occurs when the valves within the veins that regulate blood flow become weakened, allowing blood to pool and the veins to dilate. Varicocele affects 15-20% of all males and is found in up to 40% of men being evaluated for infertility, making it the most common correctable cause of male infertility.

Varicocele develops most commonly during puberty and is much more frequent on the left side due to the anatomy of the venous drainage system. The left testicular vein drains into the left renal vein at a 90-degree angle, creating more resistance to blood flow compared to the right side, where the testicular vein drains directly into the inferior vena cava. This anatomical difference explains why approximately 85-90% of varicoceles occur on the left side.

Most varicoceles are asymptomatic and discovered incidentally during physical examination or fertility evaluation. When symptoms occur, they typically include a dull ache or heaviness in the scrotum that worsens with standing or physical activity and improves with lying down. The enlarged veins are often described as feeling like a "bag of worms" on palpation. In young males, varicocele can affect testicular growth and development, which is one indication for surgical correction.

The mechanism by which varicocele affects fertility is not completely understood but likely involves increased testicular temperature due to pooled blood, reflux of metabolites from the adrenal and kidney, and oxidative stress affecting sperm production. Surgical correction (varicocelectomy) can improve sperm parameters in many cases, though the impact on pregnancy rates varies.

Epididymal Cyst (Spermatocele)

An epididymal cyst, also known as a spermatocele, is a fluid-filled sac that develops in the epididymis, the coiled tube behind the testicle that stores and transports sperm. These cysts are benign and extremely common, found in up to 30% of men who undergo scrotal ultrasound for any reason. They typically contain clear or milky fluid that may contain dead sperm cells.

Epididymal cysts are usually discovered incidentally and cause no symptoms. They feel like smooth, round lumps separate from the testicle and are typically located at the head of the epididymis (the upper portion). Unlike testicular masses, epididymal cysts are clearly separable from the testicle on examination. Most spermatoceles remain stable in size over time, though some may gradually enlarge.

Treatment is generally not necessary unless the cyst causes discomfort or becomes very large. When treatment is needed, surgical removal (spermatocelectomy) is the definitive option. Aspiration of the cyst fluid is sometimes performed but has a high recurrence rate. It is important to note that surgery on the epididymis carries a risk of affecting fertility on the operated side, so this should be discussed with the surgeon.

Epididymitis and Orchitis

Epididymitis is inflammation of the epididymis, while orchitis is inflammation of the testicle itself. These conditions often occur together (epididymo-orchitis) and are usually caused by bacterial infection. In sexually active men under 35, the most common causes are sexually transmitted infections such as chlamydia and gonorrhea. In older men and young boys, urinary tract infections with common bacteria like E. coli are more frequent causes.

Unlike the painless swelling of hydrocele or varicocele, epididymitis and orchitis cause significant pain, tenderness, warmth, and redness of the affected scrotum. Fever and urinary symptoms may also be present. The onset is typically gradual over days, which helps distinguish it from testicular torsion, where pain develops suddenly. However, because the presentations can overlap, urgent evaluation is important when scrotal pain is present.

Treatment involves antibiotics appropriate for the likely causative organism, along with supportive measures such as rest, scrotal elevation, ice packs, and anti-inflammatory medications. Most cases resolve with appropriate treatment, though some men experience chronic discomfort. Sexual partners of men with sexually transmitted epididymitis should also be evaluated and treated.

Testicular Cancer

While testicular cancer is relatively rare, accounting for about 1% of all male cancers, it is the most common cancer in men aged 15-35. Most testicular cancers present as a painless lump or swelling in the testicle, making it essential that all scrotal masses be properly evaluated. The good news is that testicular cancer has excellent cure rates, especially when detected early.

Risk factors for testicular cancer include undescended testicle (cryptorchidism), family history of testicular cancer, previous testicular cancer in the other testicle, and certain genetic conditions. Regular testicular self-examination can help detect changes early, though there is no official recommendation for routine screening in the general population.

If a solid testicular mass is suspected, ultrasound is the primary imaging modality and can reliably distinguish between benign and potentially malignant lesions. Blood tests for tumor markers (AFP, beta-hCG, LDH) provide additional diagnostic information. When cancer is confirmed or strongly suspected, surgical removal of the affected testicle (radical orchiectomy) is both diagnostic and therapeutic.

What Are the Symptoms of Scrotal Swelling?

Symptoms of scrotal swelling vary depending on the cause but typically include visible enlargement of the scrotum, heaviness or dragging sensation, and sometimes discomfort. Pain is an important distinguishing feature - sudden severe pain is a medical emergency, while painless gradual swelling is usually less urgent but still requires evaluation.

The scrotum normally has some natural asymmetry, with the left side often hanging slightly lower than the right. This is normal and related to the longer spermatic cord on the left side. However, significant size differences or new swelling should be evaluated. The characteristics of the swelling provide important clues to the underlying cause.

Painless scrotal swelling that develops gradually is typical of hydrocele, varicocele, and epididymal cyst. The swelling may be more noticeable at the end of the day or after prolonged standing. Some men notice a heavy or dragging sensation in the scrotum. In the case of varicocele, the swelling may reduce when lying down as blood drains from the enlarged veins.

Painful scrotal swelling requires more urgent attention. Gradual onset of pain with swelling over days suggests infection (epididymitis or orchitis). Sudden severe pain, especially in young males, raises concern for testicular torsion, which is a surgical emergency. Associated symptoms such as fever, urinary symptoms, nausea, or vomiting provide additional diagnostic information.

When Symptoms Require Immediate Attention

Certain symptoms associated with scrotal swelling indicate a medical emergency requiring immediate evaluation. Sudden severe pain is the most critical warning sign, particularly when accompanied by nausea or vomiting. This presentation is characteristic of testicular torsion, where the testicle twists on its blood supply. Without prompt surgical intervention within approximately 6 hours, the testicle may be lost due to lack of blood flow.

Other urgent symptoms include rapid onset of swelling with fever and redness, which may indicate severe infection or abscess formation. Symptoms of incarcerated hernia, such as inability to reduce a known hernia, severe pain, and signs of bowel obstruction (vomiting, abdominal distension), also require emergency care. Any scrotal injury causing significant swelling or bruising warrants prompt evaluation.

When Should You Seek Medical Care?

Seek immediate emergency care for sudden severe scrotal pain, especially with nausea - this could be testicular torsion requiring surgery within 6 hours. For painless swelling or mild discomfort, schedule an appointment with your doctor within a few days to weeks. All new scrotal masses should be evaluated to rule out serious conditions.

Understanding when scrotal swelling requires urgent versus routine evaluation can be lifesaving in the case of testicular torsion while avoiding unnecessary emergency visits for benign conditions. The key differentiating factor is usually the severity and onset of pain.

Routine evaluation is appropriate for painless scrotal swelling that has developed gradually over weeks to months, mild discomfort or heaviness that does not interfere with daily activities, and swelling that you have noticed for some time but have not had evaluated. While these presentations are less urgent, they still warrant medical assessment to establish a diagnosis and determine if any treatment is needed.

Schedule an appointment with your healthcare provider within a few days if you notice new scrotal swelling, even if painless. Your doctor can perform a physical examination and order appropriate tests such as ultrasound to determine the cause. Early evaluation is important because some conditions like varicocele may affect fertility if left untreated, and ruling out serious conditions like testicular cancer provides peace of mind.

How Is Scrotal Swelling Diagnosed?

Diagnosis involves physical examination to assess the swelling characteristics, transillumination test to distinguish fluid from solid masses, and often scrotal ultrasound which provides detailed imaging of the structures. Blood tests may be ordered if infection or testicular cancer is suspected.

The diagnostic evaluation of scrotal swelling begins with a thorough medical history and physical examination. Your doctor will ask about the duration and progression of the swelling, associated symptoms such as pain, fever, or urinary symptoms, any trauma or recent illness, and relevant medical history including previous surgeries or fertility issues.

Physical examination of the scrotum is performed with the patient both standing and lying down. The doctor will assess the size, consistency, and tenderness of both testicles and epididymides, palpate for masses or irregularities, attempt to transilluminate the swelling (shine a light through it), and check if a hernia is present or reducible. The examination also includes assessment of the inguinal lymph nodes and may include abdominal examination if hernia or referred pain is suspected.

Imaging and Laboratory Tests

Scrotal ultrasound with Doppler is the primary imaging modality for evaluating scrotal swelling. This non-invasive, painless test provides detailed images of the testicles, epididymis, and surrounding structures. Doppler capability allows assessment of blood flow, which is critical in suspected testicular torsion where blood flow to the affected testicle is reduced or absent.

Ultrasound can reliably distinguish between different causes of scrotal swelling. Hydrocele appears as anechoic (black) fluid surrounding the testicle. Varicocele shows dilated veins that become more prominent with Valsalva maneuver (bearing down). Epididymal cysts appear as well-defined fluid collections separate from the testicle. Solid masses within the testicle raise concern for cancer and require further evaluation.

Laboratory tests may include urinalysis and urine culture if infection is suspected, blood tests for tumor markers (AFP, beta-hCG, LDH) if testicular cancer is a concern, and complete blood count if significant infection is present. Semen analysis may be recommended for men with varicocele who are concerned about fertility.

How Is Scrotal Swelling Treated?

Treatment depends on the underlying cause. Many conditions like small hydroceles and epididymal cysts require no treatment unless symptomatic. Inguinal hernias require surgical repair. Varicocele may be treated surgically if causing symptoms or affecting fertility. Infections are treated with antibiotics. Testicular torsion and cancer require surgical intervention.

The treatment approach for scrotal swelling varies widely depending on the underlying cause, severity of symptoms, and individual patient factors such as age and fertility concerns. Many causes of scrotal swelling are benign and may be managed with watchful waiting, while others require surgical intervention.

Conservative management with observation is appropriate for many patients with asymptomatic or mildly symptomatic hydrocele, small epididymal cysts, or varicocele that is not causing significant symptoms or fertility concerns. Supportive measures such as wearing supportive undergarments (athletic supporter or suspensory), avoiding prolonged standing or heavy lifting, and using over-the-counter pain relievers can help manage discomfort.

Treatment of Hydrocele

Hydrocele is harmless and often requires no treatment unless it causes discomfort or becomes very large. In children, communicating hydrocele often resolves spontaneously within the first year of life as the processus vaginalis closes, so watchful waiting is typically recommended. Surgical repair may be considered if the hydrocele persists beyond age 2 or is associated with inguinal hernia.

In adults, treatment options include aspiration (draining the fluid with a needle) and surgical repair (hydrocelectomy). Aspiration provides temporary relief but has a high recurrence rate and carries a small risk of infection, so it is generally reserved for patients who are not surgical candidates. Hydrocelectomy is the definitive treatment and has low recurrence rates. The surgery is usually performed as an outpatient procedure with quick recovery.

Treatment of Epididymal Cyst

Epididymal cysts are benign and typically require no treatment. Most men can be reassured that the cyst is harmless and left alone. Treatment is only considered if the cyst is large, causing significant discomfort, or the patient has strong preference for removal.

Surgical removal (spermatocelectomy) is the definitive treatment when needed. It is important to understand that surgery on the epididymis carries some risk of damaging the reproductive tract on that side, which could affect fertility. This risk should be weighed against the benefits of surgery, particularly in younger men who may want children.

Treatment of Inguinal Hernia

Inguinal hernias do not resolve on their own and require surgical repair to prevent complications. While waiting for surgery, symptoms can be managed with supportive undergarments, avoiding heavy lifting and straining, and over-the-counter pain medication. A hernia belt or truss can provide temporary support but is not a long-term solution.

Surgical options include open repair and laparoscopic (keyhole) repair. Both approaches have high success rates and the choice often depends on surgeon expertise and patient factors. Recovery typically takes a few weeks, during which heavy lifting and strenuous activity should be avoided. Most patients return to normal activities within 2-4 weeks.

Treatment of Varicocele

Varicocele treatment is considered when the condition causes significant symptoms, affects testicular growth in adolescents, or contributes to infertility. Many men with varicocele require no treatment, especially if the varicocele is asymptomatic and fertility is not a concern.

Surgical treatment options include varicocelectomy (surgical ligation of the dilated veins) and percutaneous embolization (blocking the veins using a catheter). Microsurgical varicocelectomy has the lowest recurrence rate and complication rate. Following surgery, sperm parameters often improve within 3-6 months, though the impact on pregnancy rates varies.

Treatment of Infections

Epididymitis and orchitis are treated with antibiotics appropriate for the likely causative organisms. In sexually active men under 35, empiric treatment typically covers sexually transmitted pathogens (chlamydia and gonorrhea). In older men and children, treatment targets urinary tract pathogens. The antibiotic course usually lasts 10-14 days.

Supportive care includes rest, scrotal elevation with a supportive undergarment, ice packs (wrapped in cloth) applied for 15-20 minutes several times daily, and anti-inflammatory medications such as ibuprofen. Sexual partners of men with suspected sexually transmitted infection should be evaluated and treated. Follow-up is important to ensure resolution of symptoms.

How to Perform Testicular Self-Examination

Testicular self-examination involves gently rolling each testicle between the thumbs and fingers to feel for lumps, changes in size, or abnormalities. Best performed during or after a warm shower when the scrotal skin is relaxed. Any new lumps or changes should be reported to a doctor.

Regular testicular self-examination can help men become familiar with the normal feel of their testicles, making it easier to notice any changes that may develop. While there is no official recommendation for routine screening in the general population, men at increased risk for testicular cancer (those with history of undescended testicle, family history of testicular cancer, or previous testicular cancer) may benefit from regular self-examination.

The best time to perform self-examination is during or after a warm shower or bath when the scrotal skin is relaxed. Stand in front of a mirror if possible to observe any visible changes. Use both hands to examine each testicle separately. Hold the testicle between your thumbs and fingers with both hands and gently roll it to feel the entire surface.

What Are the Potential Complications?

Most causes of scrotal swelling are benign with few complications. However, untreated inguinal hernia can lead to incarceration or strangulation (emergency). Varicocele may contribute to infertility. Delayed treatment of testicular torsion results in testicle loss. Untreated infections can spread or cause chronic pain.

The potential complications of scrotal swelling depend entirely on the underlying cause. Understanding these complications helps underscore the importance of proper diagnosis and timely treatment when indicated.

Hydrocele and epididymal cysts rarely cause complications. Very large hydroceles may be uncomfortable and interfere with daily activities or sexual function, but they do not pose health risks. Infection following aspiration is a potential complication if this procedure is performed.

Inguinal hernia carries the most serious complication risk among the common causes of scrotal swelling. Incarceration occurs when hernia contents become trapped and cannot be pushed back into the abdomen. Strangulation, where blood supply to the trapped contents is cut off, is a surgical emergency that can lead to tissue death, bowel obstruction, and sepsis if not promptly treated.

Varicocele's main complication is its potential impact on fertility. The condition is found in approximately 40% of men with primary infertility and 80% of men with secondary infertility. While the relationship is not fully understood, varicocele can impair sperm production and function. Testicular atrophy (shrinkage) may occur in severe or long-standing cases, particularly in adolescents.

Testicular torsion has a time-critical complication: if blood flow is not restored within approximately 6 hours, the testicle will likely be lost. Even with prompt treatment, some degree of testicular atrophy may occur. The untreated testicle will become nonviable and require surgical removal.