What causes one testicle to be bigger?

It’s normal for one of your testicles to be bigger than the other. The right testicle tends to be the bigger one. One of them also usually hangs a little lower than the other within the scrotum.

However, your testicles should never feel painful. And even if one is bigger, it shouldn’t be a completely different shape. See your doctor if you notice that either testicle suddenly hurts or isn’t the same shape as the other.

According to healthline, possible causes of an enlarged testicle include:

Epididymitis

This is inflammation of the epididymis. It’s usually the result of an infection. This is a common symptom of chlamydia, a sexually transmitted infection (STI). See your doctor if you notice any abnormal pain, burning when you urinate, or discharge from your genital along with inflammation.

Epididymal cyst

This is a growth in the epididymis caused by excess fluid. It’s harmless and doesn’t need any treatment.

Orchitis

Orchitis is testicle inflammation caused by infections, or the virus that causes mumps. See your doctor if you notice any pain, as orchitis can cause damage to your testicles.

Hydrocele

A hydrocele is fluid buildup around your testicle that can cause swelling. This fluid buildup can be normal as you get older, and doesn’t require treatment. However, it can also indicate inflammation.

Varicocele

Varicoceles are enlarged veins within your scrotum. They can cause a low sperm count, but normally don’t need to be treated if you have no other symptoms.

Testicular torsion

Twisting of the spermatic cord can happen when the testicle rotates too much. This can slow or even stop blood flow from your body to the testicle. See your doctor if you feel persistent testicular pain after an injury or pain that goes away and comes back without warning. Testicular torsion is an emergency that requires immediate medical care to save the testicle.

Testicular cancer

Testicular cancer occurs when cancerous cells build up in your testicle. See your doctor right away if you notice any lumps or new growths around your testicles.