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Scrotal Swelling in Children: What Is a Hydrocele?

By: Campbell Grant, MD & Christopher Jaeger, MD

A hydrocele describes fluid that collects and causes swelling of the scrotum around the testicle. Many newborn boys have this problem, though it usually goes away by around their first birthday without any treatment. Babies born prematurely are at an increased risk of having a hydrocele.

Although babies born female don't have testicles, they have a similar supporting structure in the groin called the inguinal canal; in rare cases, can also get hydroceles.

How do I know if my child has a hydrocele?

Hydroceles can occur at any age, but are most common in newborns and infants. Hydroceles usually present as a bulge in the scrotum. The hydrocele may change size throughout the day, getting worse with crying or straining and then get better at night when your child is lying down. The size of the hydrocele may also change over weeks, getting smaller or larger.

Hydroceles are usually not painful. If your child is having lots of sudden pain in the scrotum or groin and scrotal swelling, it is possible that the testicle has twisted on itself (called testicular torsion) or a piece of intestine is stuck in the groin. If you think your child may have either of these problems, you should call your pediatrician immediately or take them to the nearest emergency room.

What causes a hydrocele to form?

There are two main reasons why hydroceles form. This first way happens in the womb as a baby's testicles start growing within their abdomen. As the baby develops, the testicles travel down into the scrotum. Occasionally, this tunnel (called the processus vaginalis) does not close, leaving an opening between the scrotum and the belly. This is called a "communicating hydrocele."

The second way happens when fluid becomes trapped within the scrotum after the tunnel closes. This is called a "non-communicating hydrocele" and can also be caused by surgery, trauma or inflammation.

What is the difference between communicating and non-communicating hydrocele?

The two types of hydroceles, "communicating" and "non-communicating," refer to whether or not the hydrocele connects to the belly. In communicating hydroceles, there is an opening between the scrotum and the belly that allows fluid to freely pass between the two areas. In a "non-communicating" hydrocele the tunnel between the two has been closed, but the fluid is unable to be removed by the scrotum.

What is the difference between a hydrocele and an inguinal hernia?

Hydroceles are very similar to inguinal hernias, which happen when part of the intestines push through the inguinal canal.

In a communicating hydrocele, the tunnel can be small so that only fluid passes between the abdomen and the scrotum. Inguinal hernias often have larger openings between the belly and the scrotum. Because of the larger opening, things such as bowel or other tissue can slip through. If the bowel or tissue gets stuck, this can become an emergency. Inguinal hernias often require surgery sooner than hydroceles.

Will any tests need to be done to see if my child has a hydrocele?

Most of the time, a doctor can diagnose a hydrocele by what they see when they examine your child. Hydroceles will usually "transilluminate." This means that you can shine light through them and see the light from the other side.

Sometimes a doctor will order an ultrasound to look for a testicle in the hydrocele or to distinguish between a hydrocele and an inguinal hernia or mass.

How is a hydrocele treated?

Many hydroceles will resolve on their own. If they have not gone away by one year of age, then your child may need surgery. Your doctor will refer you to a pediatric urologist or pediatric surgeon for the procedure.

What type of surgery is done for a hydrocele?

To treat a hydrocele, a small incision is made in the groin. The surgeon will check to be sure there is no connection between the hydrocele and the abdomen that needs to be closed. The hydrocele sac will be opened to drain all of the fluid, and then the sac will be removed. The surgery generally takes between 30 minutes to an hour.

What should I expect on the day of hydrocele surgery?

Before surgery you will meet with an anesthesiologist. Surgery to repair a hydrocele is typically done under general anesthetic, although regional anesthesia can be used. Your child will be asleep during the procedure.

Once your child wakes up from surgery someone from the recovery room will call you and you will be able to be with your child.

Your child may have some pain where the incision was made or down in the scrotum. Some surgeons will inject medicine near the incision to help control pain. Your child may need to take pain medicine when they are home. Most children will not need narcotics for this procedure.

When can my child go home after hydrocele surgery?

Typically, hydrocele surgery is an outpatient or "same day" surgery---meaning your child can go home after a few hours of recovery. However, if your child has certain medical conditions they may be required to stay overnight for observation.

When should I call the doctor's office?

You will receive specific instructions for follow-up with your surgeon when your child goes home after surgery for hydrocele. However, here are some key reasons to call:

  • Bleeding or drainage from the incision

  • Redness around the wound

  • Fever above 101 F

  • Vomiting

  • Less peeing or fewer wet diapers than normal

Can a hydrocele come back?

In less than 1% of patients, a hydrocele can recur. These may go away on their own, but if they do not, your child may need to see the surgeon again.

More information

  • Inguinal Hernia in Infants & Children

About Dr. Grant

Campbell Grant, MD, is an assistant professor at the University of Kentucky. He has a special interest in robotic and endourologic surgery in children. He completed his pediatric urology fellowship at Cincinnati Children's Hospital and urology residency at George Washington University.

About Dr. Jaeger

Christopher Jaeger, MD, is a pediatric urology fellow at Boston Children’s Hospital. He serves as a fellow representative to the AAP Section on Urology Education committee and also represents all pediatric urology fellows at the AAP Section on Urology executive committee

Last Updated
American Academy of Pediatrics Section on Urology (Copyright © 2022)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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