Men's health

Swollen Testicles: 8 Possible Causes

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Medically approved by Dr Earim Chaudry
Chief Medical Officer
iconLast updated 4th May 2021

In 30 seconds…

Swollen testicles, or a swollen scrotum, can be painful and alarming. Yet, you shouldn’t jump to conclusions. There is no one single cause, and it is not recommended that you try and diagnose the problem yourself.

Possible causes for scrotal swelling include trauma, increased fluid or blood supply, and inflammation. Depending on their severity, these cases may resolve themselves over time. Yet, other causes – including testicular cancer – can be more serious.

Your GP will be able to identify the cause in your specific circumstance. But, in the meantime, apply a cold compress to the area – and avoid sudden movements that might increase the pain.

Understanding Scrotal Swelling

Swelling in any part of the body is unpleasant. But when it is your sensitive parts that are swollen, things can inevitably get a little more distressing. That’s natural.

However, while it is easy to say, panic will not help your situation. And, in many cases, it’s not deserved. There are many possible causes for swollen testicles – and many can be easily treated. Knowing the precise cause in your situation, though, is the first step to effective treatment, and to recovery.

As such, here are eight common causes of testicular swelling. Importantly, though, don’t jump to your own conclusions. Seek medical advice and get a physical examination from a professional – who will be able to help you in every circumstance.

Why are My Testicles Swollen? Some Common Causes

Without further delay, here are eight possible causes of swollen testicles – along with some of the other specific signs you should look out for. In most cases, swelling of the scrotum will be accompanied by other symptoms. Let’s take a look at what you can expect.

1. Trauma

The chances are that you will know if this is the cause of your swollen testicles. By trauma we mean physical damage resulting from a wound or injury. Alongside swelling, common symptoms you can expect are severe testicular pain, nausea, and bruising.

Depending on the severity of the injury, you will usually recover from testicular trauma. However, in some serious cases, it can be a medical emergency – and you may require surgery. In extreme circumstances, there is a chance that it can lead to infertility.

2. Increased Fluid (Hydrocele)

A hydrocele is a swelling that occurs due to the build-up of fluid in the sheath that protects the testicle. Usually, it isn’t painful or harmful, and it will normally pass on its own. However, you may feel a bit of discomfort due to the heaviness of the testicle – and scrotal pain is possible if the swelling is particularly large.

Hydroceles are common among new-born babies, and are possible in older males due to inflammation, bacterial infection, or injury.

3. Swollen Veins (Varicocele)

Varicoceles, on the other hand, are testicular swellings caused by an enlargement of the veins within your scrotum. Again, these are not usually painful and are rarely harmful, although in some circumstances they can cause infertility – as, if they are enduring, they can affect your sperm count.

The condition is caused by problems of blood flow inside your spermatic cord, which carries blood to your testicles. If there is a blockage or blood accumulates, this cord can dilate. Your testicle – almost always the one on the left side – will swell too.

It’s common during puberty, but if you notice that one testicle is larger than the other, you may be experiencing the condition even as an adult. Varicoceles are often described as varicose veins but on your scrotum – so look out for this sign too.

4. Inflamed Testicles (Orchitis)

Orchitis symptoms can include swelling in one or both testicles, fever, nausea and vomiting, and pain that can be mild or that can be severe. If left untreated, orchitis can lead to infertility – however, easy medication can ease the symptoms and make the condition go away.

Doctors do not know all of the different causes of orchitis. However, sexually transmitted diseases – such as gonorrhoea and chlamydia – bacterial infections, and mumps are all known to be possible causes. If you have had problems in your urinary tract – or if you have had surgery there – you may be at greater risk of orchitis.

5. Inflamed Epididymis (Epididymitis)

If orchitis is the swelling of the testicle itself, epididymitis is when the coiled tube at the back of each testicle – known as the epididymis – becomes inflamed. It is caused by similar problems as orchitis, and the symptoms are similar. Antibiotics will successfully make it go away.

If both your epididymis and testicles are affected, you have epididymo-orchitis, which can be treated in the same way.

6. Inguinal Hernia

While not strictly a swollen testicle, an inguinal hernia looks like a swelling in the scrotum. It is actually an internal part of your body pushing through the muscles that should normally keep it in place.

This may happen gradually, or it may occur suddenly as a result of physical strain, such as that in constipation or in heavy lifting. It can be painful, and the lump may be more obvious when you are lifting something, and may disappear when you lie down.

Surgery is the solution here, in which doctors will try to push back inside the intestine or tissue that has emerged. While complications are possible, surgery is usually highly effective.

7. Testicular Torsion

A testicular torsion is when a testicular rotates in the tissue that should hold it in place. As it rotates, the spermatic cord becomes blocked, and the result is sudden pain and severe swelling. Testicular torsion is an emergency – as, when the blood supply is cut off, the testicle is not receiving what it needs to survive.

These are most common in teenage boys – and can occur during sleep, after vigorous activity, or after injury. It is an inherited trait too, so if your father had it, you are more likely to experience torsions yourself.

Seek immediate medical attention. If treatment is not received relatively quickly, your testicle may have to be removed.

8. Testicular Cancer

Testicular cancer is not one of the more common cancers – and it affects a different demographic to more familiar cancers. If you are between 15 and 49, you are most at risk – and testicular lumps are what you should look out for.

These are usually painless and often go unnoticed. As a result, it is important for all men to be familiar with how their bodies feel. Testicular cancer is treatable and has one of the best outlooks of all types of cancer. However, you may have to have the affected testicle removed.

What to Do about Swollen Testicles

While it is useful to know the different possible causes of testicular swelling, in most cases you will not be qualified to find the correct cause of your own symptoms. If you want reliable diagnosis and effective treatment, a visit to a doctor will be necessary.

In the meantime, if your swelling is sudden and painful, apply something cold to the affected area. This will help reduce inflammation and pain. Meanwhile, you should avoid any activity that is likely to aggravate the swelling or cause further pain.

Key Takeaways: Testicular Swelling Causes

There are many possible causes for swollen testicles. Yet, from a hydrocele to testicular torsion, the severity and symptoms of each individual problem will differ dramatically. Knowing what sort of swelling you are experiencing is essential for effective treatment.

As such, if you are experiencing testicular or scrotal swelling, seek medical advice. Swelling of the testicles is not something you want to be managing alone.


While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.

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