A hydrocele is not a hernia, but the two conditions are closely related and sometimes occur together. A hydrocele is a buildup of fluid around the testicle, while an inguinal hernia happens when abdominal organs (usually a loop of intestine or fatty tissue) push through a weak spot in the groin and into the scrotum. They can look similar from the outside, both causing swelling in the groin or scrotum, which is why the confusion is so common. What connects them is that they often share the same underlying cause: a small channel in the groin that was supposed to close before or shortly after birth but didn’t.
Why These Two Conditions Get Confused
During development, a small tunnel called the processus vaginalis forms in the groin to allow the testicles to descend into the scrotum. Normally, this tunnel seals shut on its own. When it doesn’t close completely, it creates an open pathway between the abdomen and the scrotum. If only fluid trickles down through that opening, the result is a communicating hydrocele. If abdominal tissue or part of the intestine slides through the same opening, it’s an indirect inguinal hernia.
Because the root anatomy is identical, a communicating hydrocele and an indirect inguinal hernia can coexist. Fluid and intestinal tissue can both enter the same channel. This is why doctors evaluating scrotal swelling always check for signs of a hernia alongside a hydrocele, especially in children.
Communicating vs. Non-Communicating Hydroceles
Not all hydroceles carry hernia risk. There are two types, and the distinction matters.
A non-communicating hydrocele is a sealed pocket of fluid around the testicle with no connection to the abdomen. The tunnel closed normally, but some fluid got trapped during the process. This type is extremely common in newborns and typically resolves on its own within the first year of life. It has no pathway for intestinal tissue to travel through, so it poses no hernia risk.
A communicating hydrocele has an open channel to the abdomen. The swelling often changes size throughout the day, getting larger when a child is active or crying (which increases abdominal pressure) and smaller after rest or sleep. This type is more commonly associated with a hernia because the same opening that allows fluid to flow can also allow abdominal contents to slip through. A hydrocele that persists beyond 12 to 18 months is often communicating and typically requires surgery to prevent a hernia from developing.
How They Feel and Look Different
From the outside, both conditions create swelling in the scrotum or groin. But there are reliable ways to tell them apart.
A hydrocele usually presents as a painless, smooth swelling around the testicle. It feels soft and fluid-filled. One of the classic ways to check is called transillumination: when a light is held against the swelling in a dark room, a hydrocele glows because light passes through the clear fluid. A hernia, which contains solid tissue like intestine or fat, blocks the light.
A hernia is more likely to produce a visible bulge in the groin area that becomes more prominent with coughing, straining, or standing. The bulge can often be gently pushed back into the abdomen, something called “reducing” the hernia. A hydrocele generally can’t be pushed back in the same way because the fluid simply fills the space around the testicle. Hernias may also cause discomfort, a dragging sensation, or occasional sharp pain, particularly with physical activity. A simple hydrocele is rarely painful.
Large indirect hernias can extend fully into the scrotum and closely mimic the appearance of a hydrocele, which is one reason a physical exam alone sometimes isn’t enough and ultrasound may be used to confirm the diagnosis.
Risk Levels Are Very Different
One of the most important distinctions is urgency. A straightforward hydrocele is almost never dangerous. It doesn’t typically affect fertility or testicular function, and many resolve without any treatment.
An inguinal hernia carries real risks. The most serious concern is incarceration, where the intestine gets trapped in the channel and can’t be pushed back into the abdomen. This occurs in 6% to 18% of children with inguinal hernias, and in infants the rate can reach 30%. If the trapped tissue loses its blood supply (strangulation), it becomes a surgical emergency that can lead to bowel damage or testicular injury. This is why hernias are generally repaired promptly after diagnosis rather than monitored.
A hydrocele linked with an underlying infection or tumor can indirectly affect testicular function, but the hydrocele itself isn’t the cause of harm in those cases.
Treatment for Each Condition
For non-communicating hydroceles in infants, the standard approach is simply waiting. Most disappear by the child’s first birthday as the body reabsorbs the fluid. No surgery, no medication.
Communicating hydroceles that persist past 12 to 18 months are typically treated with surgery because of the ongoing hernia risk. The procedure involves closing the open channel to the abdomen, the same fundamental repair used for an indirect inguinal hernia. In children, this is most commonly done through a small incision in the groin crease. A scrotal approach, with the incision made on the scrotum itself, is sometimes used and involves less disruption to the inguinal canal, though it isn’t suitable for all cases.
Inguinal hernia repair in adults often involves reinforcing the weakened area with mesh to prevent recurrence. In children, mesh is rarely needed because the repair simply involves tying off the open channel. Both procedures are typically outpatient surgeries with recovery times measured in days to a couple of weeks rather than months.
How Doctors Tell Them Apart
The physical exam is the most important diagnostic step. A doctor will check whether the swelling transilluminates (glows with light), whether it can be reduced by gentle pressure, and whether a bulge appears or grows when the patient coughs or strains. A cough impulse, where the examiner feels a push against their finger during a cough, is a classic sign of a hernia rather than a hydrocele.
In straightforward cases, no imaging is needed. When the diagnosis is unclear, particularly with large swellings or when both conditions may be present, an ultrasound can distinguish fluid from solid tissue and identify whether the channel to the abdomen is open. In children, international guidelines emphasize that history and physical examination are the most important factors, and routine ultrasound isn’t considered necessary for a typical hydrocele.