What causes hydrocele in adults

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Last updated: April 4, 2026

Quick Answer: Hydroceles in adults are typically caused by fluid accumulation in the sac surrounding a testicle. This can result from an imbalance between fluid production and absorption, often triggered by inflammation, infection, trauma, or in some cases, tumors within the scrotum.

Key Facts

Hydroceles affect approximately 1 in 10 male infants at birth, but can also develop in adults.
In adults, hydroceles are often secondary to other conditions like infection or injury.
The fluid within a hydrocele is usually clear and straw-colored serous fluid.
A hydrocele can range in size from a small amount of fluid to a very large swelling.
While usually painless, large hydroceles can cause discomfort and make it difficult to wear certain clothing.

What is a Hydrocele?

A hydrocele is a common condition characterized by the accumulation of fluid in the sac that surrounds a testicle, known as the tunica vaginalis. This sac normally contains a small amount of lubricating fluid that helps the testicles move freely within the scrotum. When there is an imbalance between the production and absorption of this fluid, or due to other underlying factors, it can lead to a buildup, causing the scrotum to swell.

Causes of Hydrocele in Adults

Unlike hydroceles in newborns, which often resolve on their own, hydroceles in adults typically have an underlying cause that needs to be identified. These causes can be broadly categorized into:

1. Inflammation and Infection:

Inflammation of the epididymis (epididymitis) or the testicle itself (orchitis) can lead to increased fluid production within the tunica vaginalis. Infections, particularly sexually transmitted infections (STIs) like chlamydia or gonorrhea, can cause significant inflammation and subsequent fluid buildup. Other infections, such as urinary tract infections, can also spread to the scrotum and contribute to hydrocele formation.

2. Trauma or Injury:

A direct injury to the scrotum, such as a blow or a surgical procedure like a hernia repair or testicular surgery, can disrupt the normal fluid balance and lead to the development of a hydrocele. The body's inflammatory response to injury can also play a role in fluid accumulation.

3. Tumors:

Although less common, a hydrocele can sometimes be a symptom of a tumor within the testicle or scrotum. Cancerous or non-cancerous growths can affect the normal fluid dynamics and lead to swelling. It is crucial for any unexplained scrotal swelling to be evaluated by a medical professional to rule out serious conditions like testicular cancer.

4. Other Medical Conditions:

Certain medical conditions can predispose individuals to developing hydroceles. These include heart failure, kidney disease, or liver disease, which can cause generalized fluid retention in the body, including the scrotum. Conditions that affect lymphatic drainage in the area can also contribute.

5. Idiopathic Hydroceles:

In some instances, the exact cause of a hydrocele in an adult cannot be identified. These are termed idiopathic hydroceles. While less common, they still require medical evaluation to ensure no underlying issues are missed.

Symptoms of Hydrocele

The primary symptom of a hydrocele is a painless swelling in one or both sides of the scrotum. The swelling may feel smooth and firm. While typically painless, a very large hydrocele can cause:

A feeling of heaviness in the scrotum.
Discomfort, especially when walking or during physical activity.
Difficulty in wearing certain clothing or engaging in sports.
Pain or discomfort if the hydrocele is associated with an underlying infection or injury.

Diagnosis and Treatment

A doctor will typically diagnose a hydrocele through a physical examination. They may shine a light through the scrotum (transillumination) to see if the swelling is due to fluid (which will light up) or a solid mass. Further tests, such as an ultrasound, may be used to confirm the diagnosis and rule out other conditions like tumors or hernias.

Treatment depends on the cause, size, and symptoms associated with the hydrocele. Small, asymptomatic hydroceles may not require any treatment and can be monitored. If the hydrocele is large, causes discomfort, or is associated with an underlying condition, treatment options may include:

Aspiration: Draining the fluid using a needle and syringe. This is often combined with injecting a sclerosing agent to help prevent recurrence, though recurrence is common.
Surgery (Hydrocelectomy): This is the most definitive treatment, involving surgical removal of the sac that contains the fluid. It is usually recommended for persistent or symptomatic hydroceles.

It is essential for any adult experiencing scrotal swelling to consult a healthcare professional for an accurate diagnosis and appropriate management plan.