What Is a Communicating Hydrocele? Symptoms, Causes, Diagnosis, Treatment & Outlook
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer
A communicating hydrocele is a scrotal swelling in which an opening between the abdomen and scrotum lets fluid pass back and forth, so its size changes during the day [1]. In infants, watchful waiting is usually enough [1] [5]. If it persists past one year, surgery drains the fluid and closes the channel [4].
Key takeaways
What it is: A fluid-filled sac surrounding the testicle with an opening to the abdominal cavity, allowing fluid to flow in and out.
Who gets it: Anyone with testicles at any age, but very common in newborns.
Hallmark feature: Swelling that increases and decreases throughout the day.
Pain level: Usually not painful [3] [5]; can become large and uncomfortable or heavy.
Harm to fertility: None — it does not harm the testicles or the ability to have children [4].
Main risk if untreated: Can lead to an inguinal hernia, which may cause pain or a blocked intestine [4].
Typical infant course: Usually goes away on its own within the first year [3] [5].
Surgery: Hydrocelectomy — small groin incision, fluid drainage, closure of the opening — with a very good success rate.
Recovery: Most infants feel better within a few days; avoid groin-injuring activities for 2–3 weeks [4].
Outlook: Excellent — resolves without treatment in most infants; surgery is highly successful when needed [1].
What the research says
Most infant hydroceles clear on their own, but a hernia can travel with them. A clinical review of urologic conditions in infants and children notes that most hydroceles resolve spontaneously by age 1 year. Inguinal hernias, which share the same open channel, occur in 3.5% to 5% of full-term newborns and 9% to 11% of premature newborns, and an incarcerated (trapped) hernia is painful, can cause vomiting and needs prompt treatment (Simpson and Sundaram, FP Essent, 2020 [5]).
Waiting is reasonable early on, and surgery works when it is needed. A narrative review (published in German) reports that a primary hydrocele with a patent vaginal process tends to regress on its own in the first 2 years of life in newborns, and that when treatment is necessary, both open and laparoscopic surgery give good results (Filmar et al., Urologie, 2024 [6]).
What Is a Communicating Hydrocele?
A communicating hydrocele is a type of fluid-filled sac surrounding the testicle that causes swelling in the scrotum. The defining feature — and the meaning of the word "communicating" — is that it has an opening to the abdominal cavity. The abdominal cavity is the large, hollow space in the abdomen that holds vital organs such as the stomach, intestines and kidneys. It also contains abdominal fluid. When you have a communicating hydrocele, the opening allows that abdominal fluid to pass into the scrotum, and that is what causes the swelling.
The word hydrocele is pronounced "HY-dro-seel."
A communicating hydrocele can change in size throughout the day. You may notice more swelling on one side of the scrotum. The swelling may go away while lying down or sleeping, and it may increase when moving around a lot. The hydrocele usually does not cause pain, but it can become large and uncomfortable.
Anyone with testicles, no matter their age, can have a communicating hydrocele. But they are very common in newborns [3]. In newborns, they usually go away on their own within the first year [3] [5]. However, if a communicating hydrocele does not go away on its own and is not treated surgically, it can lead to an inguinal hernia [4].
Is a communicating hydrocele harmful? It will not harm the testicles or the ability to have biological children (fertility) [4]. But if it causes an inguinal hernia, harmful complications may develop — including pain or a blocked intestine [4].
Is it the same as a hernia? No. A communicating hydrocele itself is not a hernia. However, an inguinal hernia can sometimes develop if the opening is wide [4] and the hydrocele is left untreated. An inguinal hernia may be painful, and in some cases it may be dangerous.
Communicating Hydrocele Symptoms
In children, symptoms typically include:
A swollen or enlarged scrotum.
Swelling that increases and decreases throughout the day.
Older children and adults may have those same symptoms as well as:
Inflammation.
Discomfort as the scrotum swells and gets heavy.
Pain as the scrotum increases in size.
What does it feel like? If you touch a communicating hydrocele, it may feel like a soft, small water balloon in the scrotum.
Symptom | Details |
Swollen or enlarged scrotum | Most common sign, often on one side |
Fluctuating swelling | Increases and decreases throughout the day |
Position change | Swelling may go away when lying down or sleeping |
Activity change | Swelling may increase with lots of movement |
Pain | Usually painless; pain may occur as the scrotum enlarges |
Discomfort | The scrotum can feel heavy |
Texture | Feels like a soft, small water balloon |
Inflammation | Possible in older children and adults |
Infant-specific signs | Loss of appetite, difficulty feeding, nausea and vomiting, pooping less than usual (may signal a hernia) |
What Causes a Communicating Hydrocele?
A communicating hydrocele forms while the fetus is developing in the uterus.
During typical fetal development, a thin membrane called the processus vaginalis forms between the stomach lining and the scrotum. The testicles begin in the abdomen and eventually move through the processus vaginalis into the scrotum. Afterward, tissue normally blocks the opening.
But if the processus vaginalis remains open, fluid flows back and forth from the abdominal cavity through the scrotum [1] — like waves at a beach. That two-way flow of fluid is what produces the characteristic swelling that grows and shrinks through the day.
Developmental step | What happens |
Fetal development | Thin membrane (processus vaginalis) forms between stomach lining and scrotum |
Testicle descent | Testicles begin in the abdomen and move through the processus vaginalis into the scrotum |
Normal outcome | Tissue blocks the opening after descent |
Communicating hydrocele | The opening remains unblocked, so abdominal fluid flows back and forth into the scrotum |
How Is a Communicating Hydrocele Diagnosed?
Healthcare providers can usually diagnose a communicating hydrocele through a physical exam. They may shine a light through the scrotum to look for fluid around the testicle [2] [3] — a quick test that takes advantage of the fact that clear fluid lets light pass through.
A provider may recommend an ultrasound if the scrotum is very swollen or feels hard. Ultrasound imaging helps rule out other possible causes of swelling, such as testicular cancer [1] [3].
Communicating vs. noncommunicating hydrocele
Feature | Communicating hydrocele | Noncommunicating hydrocele |
Processus vaginalis | Remains open | Closes as expected |
Fluid source | Flows back and forth from the abdominal cavity | Extra fluid trapped in the scrotum |
Size pattern | Changes size throughout the day | Usually stays the same size or grows very slowly |
Typical presentation | Common at birth, very common in newborns | May be present at birth, but usually occurs after an injury to the scrotum in children and adults |
Cause in children/adults | Developmental (open channel from birth) | Often injury-related |
Communicating Hydrocele Treatment Options
In infants, a communicating hydrocele will often disappear within the first year without any treatment [3] [5]. A pediatrician will likely suggest watching the area and scheduling regular checkups every few months.
If a communicating hydrocele does not go away within a year of birth, the child may need a hydrocelectomy [3]. During this procedure, a surgeon makes a small cut (incision) in the groin, drains the abdominal fluid from around the testicle, and closes the processus vaginalis.
Treatment option | What happens | When it applies |
Watchful waiting | Regular checkups every few months while the swelling is monitored | First year of life — most hydroceles resolve on their own [5] |
Hydrocelectomy (surgery) | Small groin incision; fluid drained from around the testicle; open channel closed | If the hydrocele persists past one year of birth |
Pain relief for mild discomfort | Nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen — after checking with a provider, since not everyone can take these | Symptom relief at any stage |
Recovery time. Recovery times vary, but most infants start to feel better a few days after surgery [4]. Your baby will be able to eat and play [4]. It is a good idea for them to avoid activities that could injure the groin area for at least two to three weeks — these include climbing and using straddling toys, like bicycles and seesaws [4].
Outlook and Recovery
The overall outlook for a communicating hydrocele is good. In infants, it usually goes away on its own without any treatment. And if you or your child do need treatment, surgery has a very good success rate [1] [3].
How to feel better in the meantime. If a communicating hydrocele causes mild pain, you can help relieve it with nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen. Not everyone can take these medications, so check with a healthcare provider before taking them or giving them to your child.
Living With a Communicating Hydrocele
For parents, the hardest part is often the worry — scrotal swelling in a baby is unsettling, especially when it seems to come and go. In most cases, though, a communicating hydrocele does not need treatment and does not cause complications. Regular checkups with your child's provider are still a good idea. If the hydrocele does not go away, surgery has a good success rate, and your provider can answer any questions along the way.
When to see a healthcare provider. Call your child's provider if you notice any symptoms of a communicating hydrocele or inguinal hernia [4]:
Swelling or a lump around your infant's scrotum or just above it.
Clear pain in your infant's scrotum that may improve while resting.
Loss of appetite or difficulty feeding.
Nausea and vomiting.
Pooping less than usual.
After a hydrocelectomy, call your child's provider if they have heavy bleeding, increased swelling, increased pain, or signs of infection such as fever, chills or skin discoloration (red, purple, brown or black).
Conclusion
A communicating hydrocele is a fluid-filled sac around the testicle connected to the abdomen by an open channel. That connection lets abdominal fluid flow back and forth, producing swelling that characteristically grows and shrinks through the day — larger with activity, smaller at rest. It is most common in newborns, where it usually resolves on its own within the first year with nothing more than watchful monitoring. The condition does not damage the testicles or fertility, and it is usually painless, though it can become large and heavy.
The main reason to stay on top of it is the hernia risk: an untreated hydrocele with a wide-open channel can develop into an inguinal hernia, which can cause pain and even a blocked intestine. If the hydrocele persists past one year, a hydrocelectomy closes the channel with a very high success rate, and most infants bounce back within days. If you are caring for a child with scrotal swelling, keep regular checkups, watch for the warning signs, and rest easy knowing that the outlook is excellent in the vast majority of cases.
If you find visual explanations helpful for understanding or teaching others about children's health topics, explore Rinnit's infographic templates — designed to turn complex health topics into clear, shareable visuals.
Frequently Asked Questions
What is a communicating hydrocele?
A communicating hydrocele is a collection of fluid in the scrotum. An opening between the abdomen and the scrotum allows abdominal fluid to flow into the scrotum, causing swelling.
Why is it called "communicating"?
The term refers to the opening (communication) between the scrotum and the abdominal cavity. Fluid can pass back and forth between the two areas.
What does hydrocele mean?
A hydrocele (pronounced "HY-dro-seel") is a fluid-filled sac surrounding the testicle.
Who can get a communicating hydrocele?
Anyone with testicles, no matter their age, can have one — but they are very common in newborns.
Is communicating hydrocele common in babies?
Yes. It is very common in newborns, and most resolve on their own within the first year.
What does a communicating hydrocele look like?
It appears as a swollen or enlarged scrotum, often more on one side. The swelling can change size during the day.
Why does the swelling change size?
Because the open channel lets fluid move between the abdomen and the scrotum. Movement pushes fluid down (swelling increases), while lying down lets fluid return (swelling decreases).
Does the swelling go away when sleeping?
It may. Swelling often goes away while lying down or sleeping and increases with lots of movement.
Does a communicating hydrocele hurt?
Usually it is not painful, but it can become large and uncomfortable.
What does it feel like when you touch it?
It may feel like a soft, small water balloon in the scrotum.
Can it affect fertility?
No. A communicating hydrocele will not harm the testicles or the ability to have biological children.
Is a communicating hydrocele dangerous?
On its own, usually not. The concern is that an untreated hydrocele with a wide opening can lead to an inguinal hernia, which can cause pain or a blocked intestine.
Is a communicating hydrocele the same as a hernia?
No. But an inguinal hernia can develop if the opening is wide and the hydrocele is left untreated.
What is the difference between communicating and noncommunicating hydrocele?
In a communicating hydrocele, the channel to the abdomen stays open and the swelling changes size during the day. In a noncommunicating hydrocele, the channel has closed, extra fluid is trapped in the scrotum, and the swelling stays the same size or grows very slowly.
What causes a noncommunicating hydrocele?
It may be present at birth, but in children and adults it usually occurs after an injury to the scrotum.
When does a communicating hydrocele form?
It forms during fetal development, when the processus vaginalis membrane fails to close after the testicles descend.
What is the processus vaginalis?
A thin membrane that forms between the stomach lining and the scrotum during fetal development. The testicles pass through it to reach the scrotum, and it normally closes afterward.
Why do testicles start in the abdomen?
During fetal development, the testicles form in the abdomen and then descend through the processus vaginalis into the scrotum.
Can adults have a communicating hydrocele?
Yes. Anyone with testicles at any age can have one, though it is most common in newborns.
How is a communicating hydrocele diagnosed?
Usually through a physical exam. A provider may shine a light through the scrotum to look for fluid around the testicle.
What is the light test for hydrocele?
Providers shine a light through the scrotum (transillumination) to see whether fluid is present around the testicle.
When is an ultrasound needed?
If the scrotum is very swollen or feels hard, an ultrasound helps rule out other causes of swelling, such as testicular cancer.
Does a communicating hydrocele need treatment?
Often no — in infants it usually disappears within the first year without treatment, with regular monitoring.
What is watchful waiting for hydrocele?
The provider monitors the swelling with regular checkups every few months while waiting for it to resolve on its own.
When is surgery needed for hydrocele?
If a communicating hydrocele does not go away within a year of birth, surgery (hydrocelectomy) may be needed.
What is a hydrocelectomy?
A surgical procedure in which a surgeon makes a small incision in the groin, drains the abdominal fluid from around the testicle, and closes the processus vaginalis.
Is hydrocelectomy successful?
Yes — surgery has a very good success rate.
How long is hydrocele surgery recovery?
Most infants start to feel better a few days after surgery. Full activity caution lasts at least two to three weeks.
What activities should be avoided after hydrocele surgery?
Activities that could injure the groin, such as climbing and using straddling toys like bicycles and seesaws, for at least two to three weeks.
Can my baby eat and play after hydrocele surgery?
Yes — most infants can eat and play within a few days of surgery.
What pain relief is safe for hydrocele discomfort?
NSAIDs or acetaminophen may relieve mild pain, but check with a healthcare provider first, since not everyone can take these medications.
When should I call the doctor about scrotal swelling?
Call your child's provider for swelling or a lump around the scrotum or just above it, clear scrotal pain that may improve with rest, loss of appetite or feeding difficulty, nausea and vomiting, or pooping less than usual.
What are signs of a hernia complication?
Pain, nausea and vomiting, poor feeding, and reduced bowel movements can signal a developing inguinal hernia. Seek care promptly.
When should I call the doctor after hydrocelectomy?
Call for heavy bleeding, increased swelling, increased pain, or signs of infection such as fever, chills, or skin discoloration (red, purple, brown or black).
What is an inguinal hernia?
A condition where tissue pushes through the groin opening. In the context of hydrocele, it can develop through the same open channel and may be painful or dangerous.
Can an inguinal hernia be dangerous?
Yes, in some cases — for example, if it blocks the intestine.
Does a communicating hydrocele go away by itself?
In newborns, it usually resolves on its own within the first year.
What if the hydrocele is still there after one year?
The child may need a hydrocelectomy to drain the fluid and close the opening.
Is the outlook good for communicating hydrocele?
Yes — the overall outlook is good. Most infant cases resolve without treatment, and surgery has a very good success rate when needed.
Can a communicating hydrocele come back after surgery?
Recurrence is uncommon because the procedure closes the open channel, but your provider will continue to monitor during follow-up.
Should I worry if the swelling comes and goes?
Coming-and-going swelling is actually characteristic of a communicating hydrocele and is usually not a cause for alarm. Regular checkups are still recommended.
Who treats a communicating hydrocele?
Pediatricians typically monitor the condition and refer to pediatric surgeons or urologists if surgery is needed.
Can a communicating hydrocele be prevented?
No — it results from natural fetal development and cannot currently be prevented.
Related Reading
References
Conjeevaram R, Huzaifa M, Leslie SW. Hydrocele. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Updated September 13, 2026. PMID 32644551. https://www.ncbi.nlm.nih.gov/books/NBK559125/
Merck Manual Consumer Version. Scrotal swelling. Full review September 2024 by Geetha Maddukuri, MD; last updated February 2026. Merck Manual Consumer Version. https://www.merckmanuals.com/home/men-s-health-issues/men-s-health-symptoms/scrotal-swelling
Urology Care Foundation. Hydroceles and inguinal hernia. Urology Care Foundation. Updated March 2024. https://www.urologyhealth.org/urology-a-z/h/hydroceles-and-inguinal-hernia
Cleveland Clinic. Communicating Hydrocele. Accessed November 4, 2026. https://my.clevelandclinic.org/health/diseases/16303-communicating-hydrocele
Simpson M, Sundaram V. Urologic conditions in infants and children: inguinal hernia, hydrocele, and cryptorchidism. FP Essent. 2020;488:16-20. PMID: 31894951. https://pubmed.ncbi.nlm.nih.gov/31894951/
Filmar S, Gross AJ, Hook S, et al. [Hydrocele]. Urologie. 2024;63(6):607-617. PMID: 38780784. https://doi.org/10.1007/s00120-024-02367-7
Medical disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions about a medical condition or before making decisions about treatment. Never disregard professional medical advice or delay seeking it because of something you have read here.
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