Most hydroceles are harmless and cause no immediate danger, but leaving one untreated indefinitely can lead to real problems. The fluid buildup can affect fertility, mask serious conditions like testicular cancer, become infected, or grow large enough to cause chronic discomfort and skin damage. Whether you need treatment depends on the type of hydrocele, its size, and whether it’s getting worse.
Many Hydroceles Resolve or Stay Harmless
A hydrocele is a collection of fluid around the testicle, and in many cases it causes nothing more than mild swelling. In infants, hydroceles frequently resolve on their own by age two without any intervention. In adults, a small, stable hydrocele that isn’t growing may never cause a problem. The concern starts when a hydrocele persists, enlarges, or develops alongside other symptoms like pain or redness.
The risks of not treating a hydrocele aren’t sudden or dramatic in most cases. They build gradually over months or years. That slow progression is actually part of the problem: because a hydrocele feels benign, people often ignore it until complications have already developed.
How a Hydrocele Affects Fertility
One of the most significant consequences of a long-standing hydrocele is its effect on sperm production. This happens through two mechanisms that work together.
First, the fluid surrounding the testicle acts as an insulator. Water holds heat exceptionally well, and the scrotum is designed to keep the testicles slightly cooler than body temperature. A hydrocele disrupts that cooling system. Research shows that semen quality drops by roughly 40% for every 1°C rise in scrotal temperature, which makes even a modest temperature increase meaningful over time.
Second, a larger hydrocele creates physical pressure on the testicle and its blood supply. Reduced blood flow impairs the cells responsible for making sperm. In studies comparing men with and without hydroceles, the hydrocele group had significantly lower sperm counts (about 2.3 million per milliliter versus 4.8 million) and reduced sperm motility. Testicular biopsies from hydrocele patients found complete arrest of sperm production in 8% of cases and partial arrest in another 10%. Physical changes to the testicle itself, including atrophy in 8% of patients and flattening in 22%, were also documented.
Even a nontense hydrocele, one that isn’t particularly large or firm, can affect sperm count and motility. If you’re planning to have children, a persistent hydrocele is worth addressing.
The Risk of Hiding Testicular Cancer
A hydrocele can make it impossible to properly examine the testicle, even for an experienced physician. The fluid surrounding the testicle obscures lumps and masses that would otherwise be easy to detect during a physical exam. This is a well-documented clinical problem: testicular tumors have been discovered only after a hydrocele was drained or surgically removed, sometimes after the cancer had already spread to lymph nodes.
Testicular cancer typically presents as a painless lump in the scrotum. When a hydrocele is already causing scrotal swelling, that lump becomes invisible. Because a hydrocele is considered benign, patients and sometimes even doctors may not pursue further imaging, which delays diagnosis. If you have a hydrocele, an ultrasound can see through the fluid and check the testicle underneath. This is a simple, noninvasive step that rules out a hidden tumor.
Infection and Serious Complications
An untreated hydrocele can become infected, transforming from a harmless fluid collection into an urgent medical problem. When the hydrocele fluid becomes infected, the condition is called a pyocele. This can happen if bacteria reach the hydrocele through the bloodstream or, in the case of communicating hydroceles (those connected to the abdominal cavity), through events like a ruptured appendix.
Infected hydroceles can be severe. Case reports have documented hydrocele infections progressing to Fournier’s gangrene, a rapidly spreading, life-threatening infection of the skin and tissue in the groin. While this is uncommon, it underscores why sudden pain, redness, warmth, or fever in the setting of a known hydrocele demands immediate medical attention.
Other complications that can develop over time include hematocele (bleeding into the hydrocele sac, often after trauma), rupture during physical activity or sexual intercourse, and calcification of the hydrocele wall in chronic cases. Chronic, large hydroceles can also cause skin irritation and breakdown where the thighs and scrotum rub together, a condition called intertrigo.
Connection to Inguinal Hernia
A communicating hydrocele has an open channel between the scrotum and the abdominal cavity. This same channel can allow abdominal contents, typically a loop of intestine, to push through, creating an inguinal hernia. About 6% of communicating hydroceles in one surgical series were found alongside a hernia. An inguinal hernia that becomes trapped or strangulated (cutting off blood supply to the intestine) is a surgical emergency. If your hydrocele changes size throughout the day, getting larger when you stand and smaller when you lie down, it’s likely communicating and carries this additional risk.
What Happens as a Hydrocele Grows
A hydrocele that goes untreated for years can grow quite large, sometimes reaching the size of a grapefruit or bigger. At that point, the physical burden alone becomes a problem. Walking, exercising, sitting comfortably, and sexual activity all become difficult. The weight and bulk of a giant hydrocele can cause chronic groin and back pain, skin thickening, and recurrent skin infections in the scrotal folds. In extreme cases, the penis can become buried within the swollen scrotal tissue, causing both urinary difficulties and sexual dysfunction.
Chronic hydroceles also develop structural changes that make eventual treatment more complicated. The hydrocele sac can calcify, and stones can form within the fluid. Surgery on a long-standing, large hydrocele carries higher risks of wound infection and slower healing compared to earlier intervention.
Treatment Options and Recurrence
When treatment is needed, the two main options are needle aspiration (draining the fluid with a syringe) and surgical repair (hydrocelectomy). The difference in long-term results is significant. Aspiration is less invasive but has a high failure rate: in one prospective study, about 35% of patients who had aspiration with a hardening agent injected into the sac saw the hydrocele return within three months. When aspiration was repeated, every single patient developed a recurrence.
Surgical repair is the more definitive option. It involves removing or repositioning the sac that produces the fluid, and recurrence rates are much lower. Recovery typically takes a few weeks, with most people returning to normal activity within that time. For children whose hydroceles haven’t resolved by age two, current guidelines recommend surgical repair at that point.
If you’ve been told you have a hydrocele and it’s small, painless, and stable, monitoring it is a reasonable approach. But if it’s growing, causing discomfort, affecting your fertility plans, or hasn’t been evaluated with an ultrasound, those are all reasons to move toward treatment rather than continued observation.