What Is a Hydrocele?

Most men notice it gradually: one side of the scrotum looks and feels fuller than the other, heavier by the end of the day, but not especially painful. A common cause is a hydrocele — a collection of clear fluid in the thin sac that surrounds the testicle. That sac normally holds only a trace of fluid so the testicle can move freely; when fluid builds up faster than the body absorbs it, the swelling slowly grows. The video above shows the operation used to correct it, and this guide walks through what to expect, from the first check to recovery at home.

Before anything is decided: the examination

Expect your doctor to start by asking when you first noticed the swelling and whether it changes during the day, then to examine the scrotum gently, feeling whether the swelling is soft and fluid-filled and whether the testicle itself can be felt separately. A small light is sometimes shone through the swelling — fluid lets light pass in a way solid tissue doesn't, which supports the diagnosis. An ultrasound scan is often arranged as well, because it can confirm that the swelling is fluid and give a clear view of the testicle inside it. That checking step matters: a swelling in this area isn't always a hydrocele, and a new, painful swelling needs prompt assessment rather than watchful waiting — our article on testicular torsion explains why sudden pain there is treated as an emergency. If you'd like to see how a clinician works through this kind of examination, this site also carries a longer video, "Scrotal swelling exam", recorded for students learning the technique.

When is treatment suggested?

Not every hydrocele needs an operation. A small one that isn't growing and doesn't bother you may simply be kept under review, and in babies hydroceles often settle on their own during the first year or so of life. Surgery tends to be suggested when the swelling keeps enlarging, feels heavy or uncomfortable, gets in the way of clothing or activity, or when the examination leaves any doubt about what's underneath. There isn't a medicine that drains a hydrocele away, which is why the choices are usually between monitoring it and repairing it.

The operation, step by step

The video at the top of this page follows a real outpatient repair, a little over six minutes long. It's German-narrated and uses the Lord technique on a pronounced left-sided hydrocele, and what you see matches the usual sequence: the skin is cleaned and sterile drapes are placed, a short incision is made, and the fluid-filled sac is opened so the clear fluid can drain away. The surgeon then folds and stitches the sac back on itself — the plication step in the Lord approach — so there's no loose pocket left for fluid to collect in again, before returning the testicle to its normal position and closing the wound with a dressing. Other repairs handle the sac slightly differently, by removing or turning it back, and your surgeon can explain which approach they plan in your case. The operation is commonly done as a day case under anaesthesia, so most people go home the same day.

Settling back in at home

Some swelling and bruising afterwards is normal and can look worse before it looks better — the area may stay somewhat fuller than the other side for a while as tissues settle. Supportive underwear, rest for the first days, and following the wound-care instructions you were given all help. You'll usually be told what to watch for, such as increasing pain, redness, fever, or the wound opening, and who to contact if any of that happens. Most people ease back into desk work and light activity fairly soon, holding off on heavy lifting and sport until their follow-up advice says otherwise.

Frequently Asked Questions

Is a hydrocele dangerous?

A hydrocele itself is usually harmless and doesn't damage the testicle or affect fertility. The reason it still deserves an examination is that the swelling needs to be confirmed as fluid — other causes of scrotal swelling need different care, and the check is what tells them apart.

Can a hydrocele go away on its own?

In babies, often yes, which is why doctors commonly watch and wait in the first year or so. In adults, an established hydrocele rarely disappears by itself, so the realistic options are monitoring it or having it repaired if it bothers you.

Will the fluid come back after surgery?

Recurrence is uncommon after a repair, because the operation deals with the sac itself rather than just draining the fluid. Simply drawing fluid off with a needle tends to be temporary for the same reason — the pocket remains — which is why it's not usually offered as the lasting fix.

MedicalVideos.com has published trusted medical videos since 2007. The site was founded by Dr. Mohamed Ibrahim, MD, PhD — physician-scientist.

Educational only — this article is general information about hydroceles, not medical advice and not a diagnosis. If you notice a new scrotal swelling, have it examined; sudden severe pain in the testicle is an emergency and needs immediate care.