Varicocele is when veins in the scrotum become enlarged and they may look or feel like ‘a bag of worms’.

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Medically reviewed by

Dr Darren Katz

What is a varicocele?

A varicocele occurs when the veins in the scrotum that drain blood from the testis (testicle) become abnormally dilated and large.

Varicoceles become increasingly common with age. The incidence is very low (less than 1%) under 1 years of age, increasing to around 15% in healthy young men. Varicoceles affect around 75% men aged 80-89 years.

A varicocele occurs most commonly on the left side. About half of men with a varicocele only have it on the left side; in the other half, most have varicoceles on both sides. Varicocele on only the right side occurs in fewer than 1 in 50 men with a varicocele.

Symptoms of a varicocele

Varicoceles cause pain in 2-10% of men who have them, but usually there are no symptoms. In a minority of men, varicoceles can impact fertility.

Men who seek help for treating varicoceles describe a heavy dragging feeling towards the end of the day or on standing for prolonged periods. The discomfort is not sharp or very intense and usually resolves when they lie down.

Causes of a varicocele

Varicoceles are caused by a backup of blood in the veins within the scrotum.

There are some differences in anatomy between the right and left sides of the body that make varicocele more common on the left.

Varicoceles are more likely to occur in men with varicose veins in their legs, or those whose fathers or brothers have a varicocele.

Diagnosis of a varicocele

Your doctor can diagnose varicocele by performing an examination.

They may examine the size and firmness of your testes (testicles) to see if your varicocele is causing possible problems with your testicular function.

Sometimes, varicoceles are diagnosed during an examination to investigate possible causes of infertility.

Usually, there are no additional tests needed to diagnose varicoceles, unless there are concerns about fertility. In these cases, a semen analysis might be performed. Some doctors might suggest measuring your testosterone levels, but this is not a standard test.

In some men it can be difficult to perform a thorough examination of the scrotum, so an ultrasound scan might be necessary. If a varicocele is seen using ultrasound but is very small, in the vast majority of cases no treatment will be necessary.

Treatment of a varicocele

There are several surgical procedures that can be used to treat a varicocele, but treatment is not always necessary.

Health effects of a varicocele

Varicoceles may inhibit development of sperm by the testes. Whether or not testosterone production by the testes is affected is not known for sure, but if it is the effect is likely to be very small. Surgical correction of varicocele can reverse these problems.

What to do about a varicocele

If you have genital pain or notice any change in the appearance of your genitals, you should see your doctor.

Varicoceles may not pose a threat to your health, but it’s worth asking your doctor to help you keep an eye on it.

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