Swollen testicles - what's behind it?


A swollen testicle is a symptom that can have very different possible causes. Most of the time, the underlying condition can be treated and the symptom will decrease. However, in some cases the swelling persists. In any case, if you have swelling in one or both testicles, you should consult a doctor to clarify the cause. While benign causes are more common, it can also be a malignant condition in young men and only have a good chance of a cure if treated in a timely manner. In addition, early diagnosis and treatment of testicular swelling is important, as otherwise there is a risk of loss of fertility.

Causes of testicular swelling

The swelling of one or both testicles can be caused by water retention, inflammation, or benign or malignant growths. There are a number of possible causes for swelling.

With a so-called testicular torsion, for example, the testicle is twisted around its own axis. This is cut off by the blood supply and an extremely painful build-up of blood and fluid occurs in the testicles. Epididymitis is also very painful and responsible for swelling due to water retention. Inflammation is often caused by bacteria that are sexually transmitted. But it can also be the result of a urinary tract infection. Another cause that leads to a swollen testicle is the so-called water break (Hydrocele). Water is retained in the testicles. This in turn can have various causes (for example, congenital or as a result of a healed inflammation). A hydrocele is usually harmless and does not cause pain. Nevertheless, an examination should also be carried out here and a decision should be made on a possible need for therapy.

Read more on the topic: What are the causes of testicular inflammation?

Furthermore, direct injury to one or both testicles, such as after a kick or an accident, can lead to swelling. The testicles have multiple shells that can tear when subjected to such blunt force. As a result, there is bleeding and swelling. In addition, in the case of swelling of the testicles (especially if only one testicle is affected), it must always be remembered that a benign or malignant tumor may be the cause. The swelling is then often hard and coarse and usually does not cause any pain. Malignant tumors can then be expected more frequently, but the chances of a cure in testicular cancer are very good these days. An early examination by the doctor is crucial in order to initiate therapy in good time if necessary. The longer you wait, the less the chances of a cure and the more intensive the necessary measures.

Testicular swelling can also be caused by a varicose vein on the testicle. As a result of the disturbed blood backflow in the testicular veins, blood accumulates in the testicles, which leads to an increase in the size of the testicle. You can find more about this at: Varicose veins on the testicles - It's that dangerous!

Unilateral testicular swelling

In most cases, the testicle is swollen on one side only. The most common causes of testicular swelling manifest themselves in most cases only on one testicle. Both testicular twisting and water breakage occur almost exclusively on one side. Inflammation and an injury as the cause of the swelling also usually only appear on one side at the beginning. However, the other testicle can swell as it progresses. With unilateral swelling that continues to grow and often does not cause pain, testicular cancer must always be considered as a possible cause. Therefore, a timely examination should be carried out by a doctor.

Swollen testicles after inguinal hernia surgery

After inguinal hernia surgery, a swollen testicle on the surgical site is a common temporary complication. The inguinal canal is in direct anatomical connection with the testicles. As a result of the procedure, swelling occurs (especially due to the retention of water). This can then spread through the inguinal canal to the testicle. In addition, there may be a bluish and later yellowish discoloration of the skin of the scrotum, which is caused by a bruise. As a rule, the swelling disappears completely within a few days and no later than two weeks. If this is not the case, if the swelling is very pronounced or if it continues to increase over time, a doctor should be consulted.

Swollen testicle after vasectomy

At a vasectomy the vas deferens are severed in order to induce an inability to conceive in men. During this surgical procedure, so-called lymphatic tracts, which transport the tissue fluid away, can also be damaged. As a result, one or both testicles can swell temporarily or permanently. However, as with any surgery, inflammation can also be a complication that leads to swollen testicles. The swelling of the testicle after a vasectomy often does not cause any significant discomfort and disappears within a few days. However, if this is not the case and there is severe pain, fever or fatigue, a doctor should be contacted as soon as possible.

Accompanying symptoms of testicular swelling

A common accompanying symptom of a swollen testicle is pain. Based on this symptom, it can already be estimated which causes are more likely and which are not. While an inflammation and a twisted testicle are usually very painful, the water breakage and testicular cancer are often not painful either. In most cases, the pain from twisting the testicles starts very suddenly and can be accompanied by symptoms such as nausea and vomiting. An inflammation can also lead to reddening and overheating of the scrotum. The epididymitis also often leads to fever and a general feeling of illness with exhaustion and aching limbs.

Read more about this at: I recognize epididymitis by these symptoms

With every swelling, a feeling of pressure or tension is also possible as an accompanying symptom. This is possible especially in the case of a pronounced water break.


If pain is an accompanying symptom of a swollen testicle, it makes certain causes more likely and others less likely. The epididymid inflammation, an injury and the twisted testicle usually cause very severe pain, which often pulls into the groin or stomach. When the testicles were twisted, the pain usually started very suddenly and intensely. In the case of inflammation, the symptoms tend to appear more slowly and continue to increase over time. The possible cause can be assumed based on the course and the nature of the pain. However, a definite diagnosis can only be made by a doctor.

Swollen testicles in children

A swollen testicle in children can have several causes and in some cases it needs to be treated very quickly. Testicular torsion (twisting of the testicle) is more common in childhood than in adults. The twist can already be triggered by an everyday movement such as crawling or cycling. The child then usually complains of sudden severe pain in the testicles and often in the abdomen. The affected testicle swells. In such a case, rapid treatment is necessary, otherwise the testicle can die within a few hours. The testicle is untwisted and fixed to the scrotum in a small surgical procedure. In babies and toddlers, water breakage is also a common cause of swollen testicles. This is usually rather harmless and often resolves on its own. On the other hand, infection with mumps can be dangerous in children who have not been vaccinated. Inflammation of the testicle can cause swelling, which can ultimately lead to infertility. Testicular cancer as a cause of swollen testicles in children is extremely rare, but it cannot be ruled out either. In any case, the child should be examined at an early stage so that it is certain what the cause of the swelling is and, if necessary, timely treatment can be given.


The most important measures so that the doctor can make the correct diagnosis of a swollen testicle are, on the one hand, a conversation between doctor and patient (anamnesis) and, on the other hand, the physical examination. During the conversation, the doctor can usually make a suspected diagnosis based on the patient's information about how long the swelling has existed and whether it is painful. The additional palpation of the scrotum and testicles often makes it clear what the cause of the swelling is. If necessary, the doctor examines the scrotum with a lamp or carries out an ultrasound examination. Further diagnostic measures may be necessary depending on the cause. If there is inflammation, for example, the inflammation levels in the blood are checked and if there is a suspicion that testicular cancer is involved, diagnostic imaging tests (e.g. CT or MRI) are used to see whether the tumor has already spread.


Due to the multitude of possible causes that can be behind a swollen testicle, there are also different forms of treatment. Epididymitis is treated primarily through bed rest, cooling and elevating the scrotum. If necessary, anti-inflammatory and analgesic medications and an antibiotic should also be taken. If there is a serious injury that has caused bleeding in the scrotum or if the testicle is twisted, emergency surgery is often necessary to preserve the testicle. In the case of testicular cancer, too, a prompt operation is usually necessary, in which the testicle has to be removed. Radiation or chemotherapy is often not necessary if treated in good time. A water rupture (hydrocele) as the cause of a swollen scrotum, on the other hand, often does not require an operation and does not require special treatment. Surgical therapy may only be necessary if the swelling causes symptoms or is very pronounced. In any case, a swollen testicle should be examined by a urologist at an early stage so that he can assess whether treatment is necessary, and if so, which one.

Duration of testicular swelling

How long a testicle has been swollen depends on the underlying cause of the swelling. In the event of inflammation or an injury, this usually subsides within a few days by cooling and elevating the scrotum and, if necessary, anti-inflammatory medication. In many cases, swelling caused by a water burst will resolve itself spontaneously over time. This can take weeks to months. In some cases, however, the swelling remains lifelong if left untreated. Whether surgical therapy is necessary depends on the doctor's assessment. If a malignant disease (testicular cancer) is the cause of the swelling, it will not go away by itself but will continue to increase over time. In such a case, a prompt examination by the family doctor or urologist is urgently necessary in order to rule out testicular cancer or at least to be able to treat it early.

More information about swollen testicles can be found here:

  • Testicular swelling
  • Testicular torsion
  • Water break in the testicle (hydrocele)
  • Inflammation of the testicles
  • Epididymitis
  • Acute scrotum