What is a hydrocele?

A hydrocele is a fluid-filled sac around the testicle inside the scrotum. The fluid is clear, comes from the abdominal cavity, and accumulates because of a small remaining connection that should have closed before birth.

The same anatomical defect that causes inguinal hernias also causes hydroceles — they are the same problem on a spectrum. In a hernia, intestinal contents come down; in a hydrocele, only fluid does.

Two types you should know

Non-communicating hydrocele

The connection has closed off, but fluid was trapped inside the scrotum at birth. This type:

  • Stays roughly the same size day to day
  • Is not connected to the abdomen anymore
  • Almost always resolves on its own as the body absorbs the fluid

Communicating hydrocele

The connection between abdomen and scrotum is still open, allowing fluid to flow back and forth. This type:

  • Changes size during the day — smaller in the morning, larger by evening
  • May enlarge when the child cries or strains
  • Is essentially the same anatomy as an inguinal hernia, just with fluid alone passing through
  • Less likely to resolve on its own

How is it diagnosed?

The diagnosis is usually clinical — a soft, painless scrotal swelling that transilluminates (a light shone behind it makes the whole scrotum glow). Ultrasound is sometimes used to confirm or to rule out other causes of scrotal swelling.

When does it need treatment?

The standard recommendation is watchful waiting until age 1–2 years. By that time, most non-communicating hydroceles have resolved. If the hydrocele persists past age 2, or if it is clearly communicating and causing concern, surgery is recommended.

The reasoning for treating persistent hydroceles is similar to inguinal hernias: as long as the connection to the abdomen exists, there is a small risk that bowel could one day push through it.

Sudden severe scrotal pain is always an emergency — even in a child with a known hydrocele. The most important condition to rule out is testicular torsion, where the testicle twists and loses its blood supply. Go to the emergency department immediately for any sudden, severe pain.

What does surgery involve?

Hydrocele surgery in children is almost identical to inguinal hernia repair. Through a small incision in the groin crease, the surgeon identifies the connection to the abdomen, drains the trapped fluid, and ties off the connection with a dissolvable suture.

The procedure usually takes 30–45 minutes. Most children go home the same day.

Recovery

Recovery is rapid. Some swelling and bruising of the scrotum is normal for 1–2 weeks. Children typically return to normal activities within a few days, with strenuous activity and rough play avoided for about 2 weeks.

Recurrence is uncommon when the operation is performed by an experienced pediatric surgeon.