Hydrocele

Introduction

A hydrocele is a fluid-filled swelling around a testicle inside the scrotum. It is usually painless. The scrotum looks enlarged on one or both sides, and adults may notice a heavy or dragging feeling that changes during the day.

In infants, hydroceles often relate to a patent processus vaginalis (a communicating channel) and frequently resolve as the channel closes. In adults, fluid can accumulate after injury, inflammation, infection, or for unclear reasons. Most hydroceles are not dangerous, but the swelling should still be examined so hernia, infection, torsion, or tumour are not missed.

Diagnosis is mainly clinical. Doctors examine the scrotum and may use transillumination—a light shone behind the swelling. Fluid typically glows with diffuse light; a solid mass such as many tumours does not transmit light the same way. Ultrasound is used when the exam is unclear.

Many hydroceles shrink without surgery. Infants are often watched for 12–24 months; adults may resolve over months, though older men sometimes have longer-lasting swelling. Persistent, large, or communicating hydroceles may need aspiration or surgery. This page is general education—not a personal operative plan.

Overview

Non-communicating hydroceles trap fluid in a closed sac around the testis. Communicating hydroceles connect to the abdomen, so size can change and hernia risk is higher—surgery is more often advised.

Pain is not typical. Sudden sharp pain suggests another diagnosis such as testicular torsion, which is an emergency because blood supply can be cut off.

Aspiration drains fluid through a fine needle but recurrence is common. Definitive repair for persistent or communicating hydroceles is usually a short day-case operation under anaesthesia with scrotal support afterward.

• Painless scrotal swelling from fluid around the testis
• Common in infants; often resolves within the first 1–2 years
• Adults may notice heaviness; size can wax and wane
• Exam ± transillumination ± ultrasound confirms fluid and checks the testis
• Observation first; surgery if persistent, large, symptomatic, or communicating
• Aspiration possible but fluid often returns
• Sudden severe testicular pain is not “just a hydrocele”—seek emergency care

What happens in the body

In fetal life a peritoneal sleeve (processus vaginalis) follows the testis into the scrotum. If it stays open, abdominal fluid can track down (communicating hydrocele). If the channel closes but fluid remains, a non-communicating hydrocele forms.

In adults, imbalance between fluid production and absorption in the tunica vaginalis—after trauma, epididymo-orchitis, or idiopathic causes—produces a similar swelling. The testis itself is usually normal, though it may be hard to feel through a tense fluid sac.

• Fluid accumulates in the tunica vaginalis around the testis
• Infant communicating hydrocele: patent processus vaginalis
• Adult hydrocele: excess production or poor absorption of scrotal fluid
• Transillumination works because clear fluid transmits light
• Communicating type can coexist with inguinal hernia risk
• Torsion and tumour are different problems that must be excluded

Signs and symptoms

Hydroceles are often noticed as a change in scrotal size rather than pain:

• Painless swelling of one or both sides of the scrotum
• A heavy or dragging sensation in adults
• Swelling that is larger later in the day or after standing (especially communicating types)
• Difficulty feeling the testis through the fluid sac
• Mild discomfort with very large swellings
• Redness or pain if infection or another acute scrotal condition is present
• Parental notice of a scrotal bulge in a baby that may change with crying
• Usually no urinary symptoms from an uncomplicated hydrocele
• Anxiety about appearance or fear of cancer—common reasons to seek care
• Sudden severe pain is atypical and needs urgent exclusion of torsion

Causes and risk factors

Many hydroceles have no single identified trigger. Context that matters includes:

• Patent processus vaginalis in infants (communicating hydrocele)
• Incomplete closure of the inguinal canal pathway after birth
• Scrotal injury or surgery in older children and adults
• Infection or inflammation of the testis or epididymis
• Idiopathic fluid imbalance in the tunica vaginalis
• Associated inguinal hernia in communicating cases
• Less often, underlying testicular pathology that needs imaging
• Not usually caused by everyday strain alone, though straining can enlarge a communicating hydrocele temporarily

Diagnosis and evaluation

A careful scrotal exam is the starting point. Typical steps include:

• History of onset, pain, trauma, infection, and size changes through the day
• Physical exam of the scrotum, testis, and inguinal canals
• Transillumination: fluid-filled hydroceles usually transmit light; many solid masses do not
• Assessment of tenderness—marked tenderness raises other diagnoses
• Scrotal ultrasound when the testis cannot be felt clearly or tumour/hernia is possible
• Urgent surgical review if torsion is suspected (sudden severe pain after injury or spontaneously)
• Differentiate hydrocele from inguinal hernia, varicocele, spermatocele, and tumour

Treatment and management

Most simple hydroceles are watched first. Procedures are considered when swelling persists or causes problems:

• Observation in infants—many resolve by 12 months and surgery is often deferred until 12–24 months if still present
• Observation in adults for several months when the swelling is small and painless
• Scrotal support for comfort with larger swellings
• Needle aspiration to drain fluid—simple but high recurrence rate
• Surgical hydrocelectomy for persistent, large, symptomatic, or communicating hydroceles
• Repair of communicating hydroceles to reduce hernia risk
• Day-case surgery under anaesthesia with a small incision, dressing, and scrotal support
• Temporary drainage tubes for about a week in some larger repairs
• Treat any concurrent infection before elective repair when possible

Prevention, self-care, and lifestyle

Not every condition is fully preventable, but the steps below may lower risk or recurrence:

• Infant communicating hydroceles relate to development—not something parents caused
• Protect the scrotum during contact sports to reduce trauma-related swelling
• Seek prompt care for epididymo-orchitis to limit inflammatory complications
• No diet or supplement reliably prevents idiopathic adult hydrocele
• After surgery, follow wound and support instructions to reduce early recurrence risk

Possible complications

Delay, missed care, or unsafe self-medication can raise the chance of complications in some cases:

• Persistent cosmetic swelling and heaviness
• Discomfort with walking or sexual activity when very large
• Infection or haematoma after aspiration or surgery (uncommon with proper care)
• Recurrence after aspiration and occasionally after surgery
• Missed inguinal hernia in communicating cases if not examined carefully
• Delayed recognition of torsion or tumour when pain or solid features are ignored

When to see a doctor or seek emergency care

Seek prompt medical advice or emergency care if any of the following apply—it is safer not to wait and see:

• Any new scrotal swelling—especially if the testis cannot be felt
• Sudden sharp testicular pain, nausea, or a high-riding testis (possible torsion—emergency)
• Redness, fever, or severe tenderness suggesting infection
• Infant hydrocele still present after 12–24 months or rapidly enlarging
• Adult hydrocele lasting beyond about six months or interfering with daily life
• Hard lump that does not transilluminate—needs prompt ultrasound review

Living with the condition

A painless hydrocele is often more alarming in appearance than in medical risk. Supportive underwear, avoiding prolonged standing when swollen, and scheduled follow-up are usually enough while watching for resolution.

If surgery is planned, arrange a day or two of reduced activity, use scrotal support, and report fever, spreading redness, or increasing pain promptly.

Parents of infants can be reassured that waiting is often appropriate, but they should return sooner for redness, vomiting with pain, or a swelling that becomes hard and irreducible.

Frequently asked questions

Is a hydrocele painful?

Usually not. The main feature is painless scrotal swelling or heaviness. Significant pain needs urgent assessment for other causes such as torsion or infection.

Do infant hydroceles go away on their own?

Often yes. Many resolve within the first year. Surgery is commonly considered only if the hydrocele persists after 12–24 months or is clearly communicating with hernia risk.

How do doctors diagnose a hydrocele?

By examining the scrotum and often shining a light through the swelling (transillumination). Ultrasound is added when the diagnosis is uncertain or the testis cannot be assessed clearly.

Is aspiration a permanent fix?

Not usually. Draining fluid with a needle can shrink the swelling temporarily, but the fluid commonly returns. Surgery is more definitive for persistent cases.

When is surgery needed?

When a hydrocele persists, grows large, causes discomfort, or is communicating (with possible hernia). Adult hydroceles that do not settle over months may also be repaired.

Can a hydrocele be cancer?

A simple fluid hydrocele itself is not cancer, but a solid mass can sometimes coexist or mimic swelling. Any non-transilluminating or hard lump needs prompt medical review and usually ultrasound.

Important caution

This article is general health education in English. It is not personal medical advice, a surgical consent form, or a diagnosis.

Every patient is different. Decisions about observation, aspiration, or surgery should follow examination by a qualified clinician.

Sudden severe testicular pain is an emergency—seek care immediately.