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What Causes a Swollen Testicle?

Doctors also refer to a swollen testicle as testicular enlargement. It occurs when the scrotum (the sac surrounding the testicles) grows abnormally large.

Testicular swelling occurs when fluid starts to accumulate around the testicle or within other parts of the scrotum. But don’t be alarmed, a swollen testicle does not always mean you have cancer. It’s typically caused by a number of other health conditions, such as:

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Testicular Torsion

This serious medical condition requires surgery nearly every time. It starts when the testicle twists the spermatic cord (which brings blood to the scrotum) and cuts off the blood supply to the testicles and scrotal tissue. Testicular torsion can occur at any time in a man’s life but is most common in young boys between the ages of 12 to 18.  


The most common symptoms for this condition include:

  • sudden, severe pain in one testicle,
  • a red scrotum in the area of the twisted testicle,
  • swelling on one side of the scrotum,
  • nausea or vomiting,
  • a testicle lump,
  • blood in the semen, or
  • the testicle is pulled to a higher position in the scrotum.

Go to the emergency room immediately if you’re experiencing any sudden and intense testicular pain or swelling.


Your doctor may give you an ultrasound to check the blood flow in the testicle and determine the severity of the torsion. Your doctor will know it’s a complete torsion if the ultrasound shows no blood flow in the testicle.

Most of the testicle can be saved if the surgery is performed within six hours of when the torsion begins. However, if the testicle is dead by the time of surgery, your doctor will need to remove the entire testicle.


This is when fluid collects around the testicle and is often harmless. The excess fluid causes a significant amount of scrotal swelling and discomfort described as a “heavy pulling feeling.” Hydroceles are much more common in infant boys, but they can occur in adult men too.


The hallmark sign of a hydrocele is a painless, round, swollen testicle that can occur on either one or both sides.

Your doctor can diagnose a hydrocele by shining a bright light at your scrotum to see if any light passes through. If it’s a hydrocele, light will pass through, but it won’t shine through for a solid lump, such as cancer.


Hydroceles typically go away on their own in children. However, adult men are often required to undergo a hydrocelectomy to get rid of a hydrocele that refuses to disappear.

Your doctor will make a small cut in your scrotum to remove the sac that surrounds the fluid. This is performed as an outpatient procedure, so you’ll be in and out within a day.

Spermatoceles & Epididymal Cysts

This is when fluid collects from the epididymis (the tube behind the back of the testicle that stores sperm). The major difference between the two conditions is that a spermatocele contains sperm while an epididymal cyst does not. Epididymal cysts often begin to form in older men after a vasectomy, but they can occur spontaneously as well.

Symptoms & Treatment

Most men don’t even know they have a spermatocele or epididymal cyst because they often go unnoticed or are painless. If an epididymal cyst grows to a large size or is uncomfortable, it can be surgically removed in a short outpatient procedure through a small scrotal incision.


This condition is an infection of the testicle and sometimes the epididymis (epididymo-orchitis). Orchitis is when one or both of the testicles are inflamed or swollen. Many different types of bacteria and viruses are the culprits for orchitis such as the mumps or sexually transmitted infections like gonorrhea or chlamydia.

Some risk factors for orchitis include being over the age of 45, having multiple sex partners, not having your mumps vaccination, getting urinary tract infections consistently, and long-term use of a catheter.


You may experience one or many of the symptoms below, including:

  • testicle pain,
  • blood in the semen,
  • penis discharge,
  • fever,
  • groin pain,
  • painful intercourse or ejaculation,
  • painful urination,
  • scrotal swelling,
  • testicular swelling, and
  • a tender, swollen groin area on the side that’s been affected.

You should visit your doctor or the emergency room if the pain starts to worsen quickly.


Before your doctor treats you for orchitis, they will examine your scrotum and may even run tests like a testicular ultrasound or a urinalysis (a urine test). Antibiotics are typically prescribed when the infection is caused by bacteria from infections like chlamydia. You may also get a script for anti-inflammatory or pain medicines. If your testicle is extremely painful, your doctor will check to make sure the testicle hasn’t twisted on itself and cut off the blood supply—a surgical emergency.

Testicular Cancer

Testicular cancer can happen at any time in a man's life. However, it's more common in men between the ages of 25 to 35 and 55 to 65. Many types of testicular tumors exist, but their aggressiveness mainly depends on the type of tumor and its advancement stage.


Testicular cancer feels like a firm, but painless irregular mass in the testicle. If you suspect that you have a testicular tumor, make an appointment with your doctor right away.


Men diagnosed with testicular cancer will need to have their testicle removed and be assessed to see whether the cancer has spread. If the cancer has moved to other parts of their body, additional surgeries or chemotherapy may be required.

How Do I Treat a Swollen Testicle?

The best way to treat any type of scrotal or testicular swelling is to treat the actual cause of the swelling. But there are a few things you can do at home to relieve any symptoms of swelling or pain. The U.S. National Library of Medicine recommends:

  • applying ice packs to the scrotum for the first 24 hours,
  • elevating the scrotum with a rolled-up towel in between your legs,
  • wearing a loose athletic supporter daily, and
  • avoiding excessive activity until the swelling has dissipated.

When You Should Call Your Doctor

Call your doctor immediately if you are experiencing unexplained or painful scrotal swelling or a testicle lump. You are welcome to make an appointment with one of our specialists today for expert evaluation and care.

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