A hydrocele (HI-droe-seel) is a type of swelling in the scrotum, the pouch of skin that holds the testicles. This swelling happens when fluid collects in the thin sac that surrounds a testicle. Hydroceles are common in newborns. They often go away without treatment by age 1. Older children and adults can get a hydrocele due to an injury within the scrotum or other health problems.

A hydrocele often isn't painful or harmful. It might not need any treatment. But it's important to see a health care provider if the scrotum looks swollen.

Often the only sign of a hydrocele is a painless swelling of one or both testicles.

The swelling might make an adult's scrotum feel heavy. In general, pain gets worse as the swelling increases. Sometimes, the swollen area might be smaller in the morning and larger later in the day.

When to see a doctor

See your health care provider if you or your child has swelling of the scrotum. It's important to find out if there are other causes of the swelling that could be treated. For example, a hydrocele might be linked with a weak point in the ab muscles that allows part of the intestine to extend into the scrotum. This problem is called inguinal hernia.

A baby's hydrocele often goes away on its own. But if your baby still has a hydrocele after a year or if the swelling gets worse, ask your child's health care provider to check the hydrocele again.

Get help right away if you or your child has sudden, terrible pain or swelling in the scrotum. It's extra important to get prompt treatment if the pain or swelling starts within a few hours of an injury to the scrotum. These symptoms can happen with certain health problems, including blocked blood flow in a twisted testicle. This problem is called testicular torsion. It needs to be treated within hours of the symptoms starting to save the testicle.

Most hydroceles are present at birth. At least 5% of newborn males have a hydrocele. Premature babies, who are born more than three weeks before their due dates, have a higher risk of having a hydrocele.

Risk factors for getting a hydrocele later in life include:

• Injury or inflammation within the scrotum.
• Infection, including a sexually transmitted infection.

A hydrocele often isn't dangerous and usually doesn't affect the ability to have a baby. But a hydrocele might be linked with a health problem that can cause serious issues. These problems include:

• Infection or tumor. Either might cause the testicles to make less sperm or not work as well as usual.
• Inguinal hernia. This can lead to life-threatening health problems.

Your health care provider should start with a physical exam. It's likely to include:

• Checking for pain in an enlarged scrotum.
• Pressing on the stomach area and scrotum to check for inguinal hernia.
• Shining a light through the scrotum. If you or your child has a hydrocele, the light will show clear fluid surrounding the testicle.

After that, you may need:

• Blood and urine tests to help find out if you or your child has an infection.
• An imaging test called ultrasound to check for a hernia, a tumor or other causes of swelling in the scrotum.

In babies, a hydrocele sometimes goes away on its own. But at any age, it's important for a health care provider to check a hydrocele. That's because it can be linked to a problem with the testicles.

A hydrocele that doesn't go away on its own might need to be removed with surgery. Some people don't have to stay at the hospital overnight after surgery. Before the operation to remove a hydrocele, you receive medicine that keeps you from feeling pain. One type of medicine puts you in a sleep-like state, too.

To remove the hydrocele, a surgeon makes a cut in the scrotum or lower stomach area. Sometimes, a hydrocele is found during surgery to repair an inguinal hernia. In this case, the surgeon might remove the hydrocele even if it's causing no discomfort.

After surgery, you might need a tube to drain fluid and a bulky bandage for a few days. You may need a follow-up exam because a hydrocele might come back.

For a hydrocele, you might see a doctor called a urologist. This is an expert in problems of the urinary and reproductive tract. Here's some information to help you get ready for your appointment.

What you can do

• Take note of your symptoms or your child's symptoms. Note how long the symptoms have lasted.
• List all medicines, vitamins and supplements that you or your child takes. Include the doses. A dose is how much you or your child takes.
• List key personal and medical information, including other health problems, recent life changes and sources of stress.
• Prepare questions to ask your health care provider.

For hydrocele, some basic questions to ask your provider include:

• What do you think is causing this swelling? Are there any other possible causes?
• What kinds of tests are needed?
• What treatment do you recommend, if any?
• What symptoms will mean that it's time to treat this condition?
• Do you suggest any limits on activity?

Feel free to ask other questions that come up during your appointment.

What to expect from your doctor

Your health care provider is likely to ask you some questions.

If your child is affected, the provider might ask:

• When did you first notice this swelling? Has it increased over time?
• Is your child in any pain?
• Does your child have any other symptoms?

If you're affected, your provider might ask:

• When did you first notice the swelling?
• Have you had any discharge from your penis or blood in your semen?
• Do you have discomfort or pain in the affected area?
• Do you have pain during sex or when you ejaculate?
• Do you have a frequent or urgent need to pee? Does it hurt when you pee?
• Have you and your partner been tested for sexually transmitted infections (STIs)?
• Do your hobbies or work involve heavy lifting?
• Have you ever had a urinary tract or prostate infection, or other prostate conditions?
• Have you ever had radiation or surgery in the affected area?

What you can do in the meantime

If you are a sexually active adult, stay away from sexual contact that could put your partner at risk of getting an STI. This includes sex, oral sex and any skin-to-skin genital contact.