What Is a Varicocele?

Abnormally Enlarged Veins in the Scrotum Caused by Defective Valves

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A varicocele is the abnormal enlargement of the veins within the scrotum (the loose sac of skin beneath the penis that houses the testicles). It occurs when the blood pools in the veins, often because the valves in the veins aren't functioning normally or a nearby structure is compressing the veins.

A varicocele often causes no symptoms and, in such cases, usually requires no treatment. Even so, it can affect sperm production, leading to infertility due to a low sperm count and/or poor sperm quality. A varicocele that causes symptoms (testicular pain), low testosterone (a sex hormone related to energy and libido), or infertility may be treated surgically.

This article looks at the symptoms, causes, diagnosis, and treatment of varicocele. It also describes the available surgical and non-surgical options when treatment is indicated.

Close-up of healthcare provider noting symptoms on a clipboard in an examination room with a male person seeking care

mihailomilovanovic / Getty Images

Gender Definitions

For the purpose of this article, "male" refers to people with penises, irrespective of the gender or genders they identify with. The terms used in this article will reflect those used in the referenced medical sources.

Types of Varicoceles

A varicocele specifically involves a structure called the pampiniform venous plexus. This is a network of tiny veins—also known as spermatic veins—that transport oxygen-depleted blood from each of the testicles as part of normal blood circulation. There are right spermatic veins and left spermatic veins.

The right spermatic veins drain into the right renal vein (which receives oxygen-depleted blood from the kidneys). The left spermatic vein drain into the left renal vein (which receives oxygen-depleted blood from multiple organs, including the heart and intestines).

This is significant anatomically because the left spermatic veins bend at a 45-degree angle as they connect the left renal vein (unlike the right spermatic veins, which are relatively straight). This bend makes them vulnerable to blood flow restriction, rather like a cinch in a garden hose.

Left-Sided vs. Right-Sided Varicocele

Because of the structural vulnerability of the left spermatic veins, a varicocele is more likely to be left-sided. An isolated right-sided varicocele is far less common, accounting for only around 2% of cases.

Bilateral (two-sided) varicoceles can also occur, albeit less commonly than a left-sided varicocele.

Symptoms of a Varicocele

A varicocele is typically asymptomatic (meaning without symptoms). In fact, it is not uncommon for people to be entirely unaware of the condition until they are faced with unexplained infertility.

If symptoms do develop, they may involve:

  • A soft lump, usually above the testicle and mostly on the left side
  • A persistent dull ache or feeling of heaviness in the testicle, scrotum, or groin
  • Worsening pain during the day, particularly in hot weather or after physical exertion
  • A smaller testicle on the affected side
  • Sharp or stabbing pain in the groin, testicle, or scrotum (less common)
  • Infertility

A large varicocele can cause a prominent scrotal mass often described as a "bag of worms."

Varicoceles and Infertility

A varicocele causes the pooling of blood in veins that service a testicle. The pooling increases the temperature within the scrotum, damaging not only sperm cells but also Leydig cells in the testicles that produce testosterone (the sex hormone responsible for sperm production).


A varicocele is a relatively common condition, affecting 15% to 20% of males and between 30% and 40% of males with infertility. It tends to develop gradually over time.

And, while a varicocele may only be noticed in adulthood, it can start to develop in early adolescence. Studies have shown that roughly 8% of males between the ages of 11 and 14 and 14% of those between 15 and 19 have varicoceles.

How a Varicoceles Occurs

A varicocele is caused by the failure of valves within the spermatic veins. These valves help regulate the flow of blood through the vein, mostly by preventing the backflow of blood. If the valves are damaged or defective, blood can start to pool, leading to varicocele.

The cause of a varicocele is unclear, but there are a number of possible explanations:

  • Geography of the left testicular vein: The perpendicular position of the left testicular veins causes blood to gush around the 90-degree corner with such force that the valves can begin to fail, causing the veins to gradually enlarge and become twisted (like varicose veins).
  • Obstruction of a testicular vein: Right- and left-sided varicoceles can also be caused by blockages in the veins. This may be due to the development of a lesion within the vessel itself or the compression of a vein by nearby organs, such as the intestines. Over time, this can cause the venous valves to become permanently damaged.
  • "Nutcracker syndrome": This is a condition in which the left renal vein is compressed by the aorta (which services the heart) and the superior mesenteric vein (which services the digestive tract). The compression can further intensify the force of blood to the left testicular veins, leading to valve damage.


A varicocele is diagnosed with a physical examination of the scrotum. The exam is commonly performed by a specialist known as a urologist, who is an expert in diseases of the urinary tract and male reproductive system.

The exam is done while you are standing. As the specialist palpates (manually examines) the scrotum and testicles, you may be asked to perform the Valsalva maneuver, during which you breathe out forcefully through your mouth while holding your nose shut. Doing so can help reveal the varicocele.

Based on how visible the varicocele is with or without the Valsalva maneuver, the urologist can classify the severity of the condition as follows:

  • Grade 1: This is a varicocele that is not visible, but you can palpate it with the Valsalva maneuver.
  • Grade 2: This is a varicocele that is not visible, but you can palpate the varicocele while standing up.
  • Grade 3: This is a large varicocele that is visible while standing up.

An ultrasound (a non-invasive device that produces images using sound waves) is generally not needed to confirm the diagnosis; a physical exam is usually enough.

However, an ultrasound may be useful in situations where a scrotal exam is difficult, such as when a person has obesity, a small scrotum, or thick scrotal skin. In cases like these, a color Doppler ultrasound can reveal the reversal of blood flow within the spermatic veins and vein diameter.


Once a varicocele is present, it will not go away on its own. This doesn't mean that it is necessarily problematic or in need of treatment. If there are no symptoms and your fertility is not impaired, a varicocele is often left untreated.

If pain is the only concern, conservative treatment is recommended before more invasive procedures are considered. This includes limitation of physical activities, elevation of the scrotum, and the use of nonsteroidal anti-inflammatory drugs like Advil (ibuprofen) or Aleve (naproxen) to temporarily relieve the scrotal pain.

If testosterone is low, this can be raised by conservative measures or with medication.

Indications for Treatment

More invasive varicoceles treatments are reserved for people with infertility who are trying to or hoping to conceive. They may also be considered for people whose severe symptoms are not relieved with pain medications or for adolescents whose testicles are not developing due to a varicocele.

There are three procedures commonly used to treat varicoceles:

  • Microsurgical varicocelectomy: This is a surgery in which a high-powered microscope is used to examine the spermatic cord through a small incision in the groin. Once the problem veins and the artery (blood inflow, which is spared) are located, the surgeon ligates (ties off) the veins to redirect blood flow to healthy veins. This technique can better isolate the problem vein and has a low recurrence rate, but requires a high level of training and can take up to two hours to perform.
  • Laparoscopic varicocelectomy: This laparoscopic surgery involves several small incisions in the abdomen. Using a narrow, specialized scope and tools, the surgeon can locate and ligate the veins higher up in the abdomen where there are fewer branches. It is an effective but less exacting technique that can take around one hour to perform.
  • Percutaneous varicocele embolization: This a procedure performed by an interventional radiologist in which a tube, called a catheter, is inserted into a vein in your thigh. After the catheter is positioned under X-ray guidance, a sclerosing (scarring) agent is released to block the problem veins and redirect the blood flow.

By normalizing blood flow, these procedures may help improve both sperm count and sperm quality, as well as testosterone. They can also help reduce chronic scrotal pain or help an undeveloped testicle "catch up" in size.

Possible complications include hydrocele (the swelling of the scrotum due to fluid build-up) and the recurrence of a varicocele. These can occur with all three procedures but are less common with microsurgical varicocelectomy.

Some studies suggest that all three techniques are similarly effective in improving conception rates.


A varicocele is the abnormal swelling of veins within the scrotum caused by blood pooling inside the veins. The condition is often asymptomatic but can cause pain and infertility in some people. A varicocele is ultimately caused by the failure of the valves within the vein (although the underlying cause is often unclear).

A varicocele is diagnosed with a physical exam and occasionally an ultrasound. Not all cases need to be treated, but those that cause infertility, chronic pain, low testosterone, or stunted testicular growth may benefit from surgical or embolization procedures.

Frequently Asked Questions

  • Are there medications to treat varicoceles?

    Not really. Some early studies have suggested that micronized purified flavonoid fraction (MPFF), an oral therapy used for people with chronic venous insufficiency, may help alleviate varicocele pain. Even so, there is no evidence that any drug can reverse or "cure" a varicocele.

  • How effective is varicocele surgery at treating infertility?

    Based on a Cochrane review published in 2021 involving 48 studies and 5,384 participants, the investigators concluded that varicocele surgery or embolization "may improve the chances for pregnancy" compared to no treatment. Of the available treatment options, microscopic varicocelectomy may offer better results and lower rates of varicocele recurrence.

  • Why is varicoceles a problem in adolescents?

    Varicoceles affect roughly 8% of males between the ages of 11 and 14. At this age, varicoceles can cause delays in secondary male characteristics due to testicular atrophy (shrunken testicles). Muscle mass, sex drive, and sperm count may also be reduced in later life.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By James Myhre & Dennis Sifris, MD
Dennis Sifris, MD, is an HIV specialist and Medical Director of LifeSense Disease Management. James Myhre is an American journalist and HIV educator.