by | Men's Health

Hydrocoeles are fluid-filled bags occurring on one or both sides inside the scrotum. They feel like a balloon filled with water.


  • Painless swelling of one or both testicles, more often the right testicle.
  • Feeling of heaviness in the affected testicle.
  • Testicle may be smaller first thing in the day, and become larger by evening.


Hydrocoeles may occur if the passage through which the testicle descends from the abdomen into the scrotum fails to close before or shortly after birth. Fluid drains from the abdomen into the scrotum where it becomes trapped causing enlargement of the scrotum. This type of hydrocoele may be accompanied by an inguinal hernia. Hydrocoeles normally disappear a few months after birth.


Hydrocoeles may also be caused by inflammation or trauma of the testicle. This type of hydrocoele is more common in older men.

Risk factors

Risk factors for developing hydrocoeles are:

  • In boys, being born prematurely.
  • In adults, having had a sexually transmitted disease or injury to the scrotum.

How are hydrocoeles diagnosed?

Hydrocoeles can be easily demonstrated by shining a flashlight through the enlarged portion of the scrotum. If the scrotum is full of clear fluid, as in a hydrocoele, the scrotum will light up (transillumination).

Your doctor will feel for tenderness of the scrotum.

You may need an ultrasound to rule out other causes of an enlarged scrotum.

If infection is suspected, you may need blood and urine tests.


Hydrocoeles are painless and usually not dangerous. Hydrocoeles are mainly treated when they cause discomfort or embarrassment, or if they get so large that they might block the testicle’s blood supply.

In boys, if a hydrocoele has not resolved 2 years after birth, surgery called an inguinal herniotomy may be considered. If the hydrocoele is accompanied by an inguinal hernia, it will usually be repaired.

In adult men, hydrocoeles may spontaneously resolve. If treatment is needed, it is either by draining the fluid with a syringe and needle (aspiration) or by a minor surgical procedure that requires little time in hospital.

Sometimes injection of sclerosing (thickening or hardening) medications may be performed after needle aspiration to obliterate (close off) the opening through the scrotal sac, preventing re-accumulation of fluid.


Possible complications after aspiration and sclerosing include infection, fibrosis, and mild to moderate pain in the scrotal area.

Occasionally hydrocoeles may be present together with an inguinal hernia, when some of the intestine also passes down into the scrotum. In this case surgery is needed quickly, to prevent obstruction of the intestine.

Although hydrocoeles are harmless, all swellings in the scrotum need checking to be sure there is nothing more serious going on.