Hydrocele

Overview

A hydrocele (HY-dro-seel) is a painless swelling in the scrotum (the pouch of skin that holds the testicles). It happens when extra fluid builds up around a testicle. In most cases, a hydrocele is harmless and goes away on its own, especially in newborns. However, sometimes it can be a sign of another problem in older boys and men.

Yes, hydroceles are common. They affect about 10% of newborn boys and up to 15% of older men.

Hydroceles can affect males of any age. They are most common in newborns and in men over 40.

Symptoms

Common symptoms

• A soft, painless swelling in the scrotum, usually on one side
• The swelling may get larger and feel heavier over time
• The scrotum may feel like a water-filled balloon
• No pain, but some men feel a dull ache or heaviness

Symptoms in children

• Swelling in one or both sides of the scrotum that may come and go
• The swelling often gets bigger when the child cries or strains
• Usually painless and does not cause discomfort

Symptoms in older adults

• A gradual increase in scrotal size over weeks or months
• A feeling of heaviness or pressure in the scrotum
• Rarely, discomfort when walking or sitting

Causes

Main causes

• In newborns: the channel between the abdomen and scrotum (processus vaginalis) does not close fully, allowing fluid to flow down.
• In older men: injury, infection, or inflammation in the testicle or epididymis (the tube that stores and carries sperm).
• Sometimes no clear cause is found (idiopathic hydrocele).

Risk factors

• Being born prematurely (increases risk of incomplete closure)
• History of testicular injury or trauma
• Infections such as epididymitis or sexually transmitted infections
• Previous surgery in the groin area

When to see a doctor

See a doctor urgently if:

• If you have sudden, severe pain in the scrotum
• If the swelling is very tender or red
• If you have a fever along with scrotal swelling

Book a routine appointment if:

• If you notice a new lump or swelling in your scrotum that lasts more than a few days
• If the swelling gets bigger over time
• If you have any concerns about a change in your scrotum

Diagnosis

A doctor can usually diagnose a hydrocele by examining the scrotum and shining a light through it (transillumination). The fluid in a hydrocele will make the scrotum glow, which helps tell it apart from a solid lump like a tumor.

Tests that may be done

• Physical exam: the doctor will feel the scrotum and check for tenderness
• Transillumination: a small flashlight is held against the scrotum
• Ultrasound: a painless scan that uses sound waves to create images of the inside of the scrotum. This is the most reliable way to confirm a hydrocele and rule out other problems.

What to expect at your appointment

The doctor will ask about your symptoms and examine your scrotum. You may be asked to lie down and then stand. An ultrasound is quick and painless — you will lie still while a small wand is moved over the scrotum. Results are usually available right away.

Treatment

Treatment depends on the size of the hydrocele, whether it causes discomfort, and whether it goes away on its own. Many hydroceles, especially in newborns and small ones in adults, do not need treatment.

Self-care at home

• For small, painless hydroceles, no action is needed — just keep an eye on it
• Wearing supportive underwear (briefs) can help with any feeling of heaviness
• Applying a cold pack (wrapped in a cloth) to the scrotum for 10–15 minutes may ease discomfort, but avoid ice directly on the skin
• Rest and avoiding heavy lifting may help if the hydrocele is due to a strain

Medical treatments

If a hydrocele is large, uncomfortable, or does not go away, a doctor may recommend a procedure called aspiration (drawing out the fluid with a needle) or a surgical repair called hydrocelectomy (removing the sac and fluid). Aspiration is sometimes used but the fluid often comes back. Surgery is more effective. No specific medications are used to treat a hydrocele directly. Antibiotics may be prescribed if there is an infection.

When is surgery considered?

Surgery is usually considered if: the hydrocele is very large and causes pain or discomfort, it does not go away after a few months in an adult, or it is suspected to be linked to a hernia or tumor. The surgery is a minor procedure done under local or general anesthesia, and most people go home the same day.

Living with this condition

Most people with a hydrocele can carry on with normal daily activities. If the swelling is large, you may feel some heaviness, but it rarely interferes with work or exercise.

Lifestyle tips

• Wear supportive underwear if you feel any discomfort
• Avoid heavy lifting or straining if the hydrocele is new or gets bigger with strain
• Check your scrotum regularly for changes — if it becomes painful or grows quickly, see a doctor

Diet and exercise

No special diet is needed. You can exercise normally as long as there is no pain. If the hydrocele is large, avoid activities that put pressure on the scrotum, like cycling for long periods. Swimming and walking are fine.

Mental health and emotional wellbeing

A hydrocele can sometimes cause embarrassment or worry, especially if it is large. It is a common and usually harmless condition. If you feel anxious, talk to your doctor or a counselor. Most treatments are straightforward and successful.

Prevention

Not all hydroceles can be prevented, especially in newborns. In older men, protecting the testicles from injury (e.g., wearing a cup during contact sports) and treating infections early may reduce the risk.

Screening programmes

There is no routine screening for hydroceles. However, regular self-examination of the testicles is a good habit for all men to notice any changes early.

Complications

If left untreated

• A large hydrocele may cause discomfort or a feeling of heaviness
• Very rarely, a hydrocele can become infected (pyocele), causing pain and fever
• In adults, a hydrocele can sometimes be a sign of an underlying problem like a hernia or testicular tumor

Long-term outlook

The outlook for a hydrocele is excellent. In newborns, most resolve without treatment. In adults, treatment — if needed — is safe and effective, and recurrence is uncommon. With proper diagnosis and follow-up, there is no long-term harm.

Find support

Local organisations

• NHS (UK) – Hydrocele information ↗ · United Kingdom
• Mayo Clinic – Hydrocele ↗ · United States

Helplines

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