A hydrocele feels like a smooth, painless swelling in the scrotum, often described as a soft, fluid-filled balloon surrounding the testicle. Most people notice a sense of heaviness or fullness on one side rather than sharp pain. The swelling can range from barely noticeable to large enough to cause visible asymmetry and a dragging sensation when you walk or stand for long periods.
How It Feels to the Touch
When you press on a hydrocele, it feels soft and smooth, similar to a water balloon. The fluid shifts slightly under your fingers but doesn’t disappear when you push on it. Unlike a hernia, which you can often push back into the abdomen, a hydrocele stays in place. The testicle itself is usually still inside the swelling, but if the hydrocele is large enough, you may not be able to feel the testicle separately through the surrounding fluid.
The surface feels even and regular. There are no hard lumps, bumps, or irregular edges. If you do feel something firm or fixed to the testicle itself, that’s a different finding worth getting checked, since testicular tumors tend to feel hard or irregular, while hydroceles feel uniformly soft and fluid-filled.
Pain, Pressure, and Heaviness
Most hydroceles are painless, especially when they’re small. What you’re more likely to notice is a dull ache or a feeling of heaviness in the scrotum, particularly after standing all day or during physical activity. The larger the hydrocele, the more noticeable this dragging sensation becomes. In surgical studies, the average hydrocele contained about 290 milliliters of fluid, roughly the volume of a small juice box, which explains why a significant one can feel genuinely heavy.
Sharp or sudden pain is not typical. If a hydrocele becomes painful, tender, or red, that can signal an infection, a hernia developing alongside it, or a different condition entirely.
Size Changes Throughout the Day
Some hydroceles, called communicating hydroceles, have a small channel connecting them to the abdominal cavity. This allows fluid to drain in and out slowly. If you or your child has this type, you’ll likely notice the swelling looks smaller in the morning after lying flat overnight and larger by evening after being upright all day. Gravity pulls fluid down through the channel, gradually increasing the swelling as hours pass.
Non-communicating hydroceles don’t have this channel. They tend to stay roughly the same size regardless of position or time of day, though they can grow slowly over weeks or months as fluid accumulates.
How It Differs From a Hernia
A hernia and a hydrocele can both cause scrotal swelling, but they feel distinctly different. A hydrocele is smooth, round, and contained entirely below the groin. You can feel the top border of the swelling, meaning your fingers can get above it. With an inguinal hernia, you typically cannot feel a clear upper edge because the bulge extends upward into the groin and inguinal canal.
Hernias also respond to pressure and movement differently. A hernia may bulge outward when you cough, strain, or cry (in infants), and it can often be gently pushed back in. A hydrocele doesn’t change with coughing and can’t be pushed away. One classic office test involves shining a light through the scrotum: fluid from a hydrocele glows and transmits light, while a hernia containing intestine blocks the light.
How Common Hydroceles Are
Hydroceles are especially common in newborns. About 1 to 5 percent of male infants have a noticeable hydrocele, even though a much larger percentage are born with the anatomical opening that can allow one to form. Most infant hydroceles resolve on their own by age one or two as the channel closes naturally.
In adults, the annual incidence is roughly 60 per 100,000 men, though only about 17 per 100,000 need surgery. Adult hydroceles usually develop from inflammation, minor injury, or no identifiable cause at all. They tend to grow slowly and don’t resolve on their own the way infant hydroceles do.
Signs That Need Attention
A stable, painless hydrocele that stays roughly the same size is generally not urgent. But certain changes warrant a visit to a healthcare provider. Watch for scrotal pain or tenderness that develops in a previously painless swelling, redness or warmth over the skin, nausea or vomiting (especially in children), or a new hard lump that feels attached to the testicle rather than surrounding it.
In infants and children, a hydrocele that grows rapidly or appears alongside a visible groin bulge may indicate an inguinal hernia developing through the same open channel. If the processus vaginalis opening is large enough, intestinal tissue can push through, which is painful and sometimes requires urgent repair.