- Most swellings are harmless: Water around the testis, or swollen veins. Many need no treatment at all.
- Sudden severe pain in one testis is an emergency. There are about six hours to save it.
- A painless lump inside the testis needs a scan now: No pain does not mean no problem.
Sudden severe pain in one testis, often with vomiting, and the testis sitting high or sideways, may be a twist. The blood supply is cut off. It can be saved if untwisted within about six hours, and the chance drops sharply after that. This is commonest in teenagers and young men. Pain that wakes a boy from sleep must never be given a wait-and-see antibiotic.
What It Usually Is
- Hydrocele: Water collecting around the testis. A smooth, painless swelling that can grow large. A torch held against it lights it up. Harmless in most adults, but one that appears suddenly, or is tense and painful, needs a scan.
- Varicocele: Swollen veins, usually on the left. Feels like a bag of worms, more obvious standing, shrinks when you lie down. Often no symptoms at all. Sometimes a dull dragging ache by evening. Matters in fertility checks. More on fertility →
- Cyst: A smooth swelling felt above and separate from the testis. Harmless. Removed only if large or uncomfortable, and usually avoided in men still wanting children.
- Infection: Pain building over a day or two, with swelling, redness, fever and often urinary symptoms. Lifting the scrotum usually eases it, which helps tell it apart from a twist. Where there is any doubt, a twist is assumed and surgery comes first.
- Hernia: Bowel coming down into the scrotum. The swelling runs up into the groin, so you cannot feel above it, and it changes when you cough or lie down. One that turns hard and tender is an emergency.
- Undescended testis in an adult: An empty scrotum on one or both sides. Carries a higher lifetime cancer risk and needs checking even in adulthood.
- A growth: A firm, painless lump felt within the testis itself, usually in a young man. A torch does not light it up.
Testicular cancer is the commonest solid cancer in men aged 15 to 40, and outcomes depend heavily on catching it early. It shows up as a painless firm lump — which is exactly why it gets left. Any new lump inside the testis needs an ultrasound now. Do not wait to see whether it changes. No pain is not reassurance.
Tests You May Need
- Examination: Whether the swelling is separate from the testis or part of it, whether you can feel above it, and whether a torch lights it up. This alone sorts out most cases.
- Scrotal ultrasound: The key test. Tells water from solid, confirms swollen veins, and checks blood flow if a twist is suspected. A scan must never delay surgery when a twist is likely.
- Urine test: If infection is suspected.
- Blood markers: If a growth is possible.
- Semen test: As part of a fertility check in men with swollen veins.
- Abdominal scan: For new swollen veins on the right, or ones that do not shrink lying down.
Treatment
- Hydrocele: A small painless one needs nothing. Surgery is offered when the size or weight becomes a nuisance. Day care. Draining it with a needle is not advised — the water comes back and repeated draining risks infection.
- Varicocele: No treatment needed if there are no symptoms. Repair is considered for ongoing pain, for a clearly smaller testis in a teenager, or as part of fertility care after discussion.
- Cyst: Usually left alone.
- Infection: Antibiotics guided by culture, with rest, support and anti-inflammatory tablets. One to two weeks of treatment; the swelling can take weeks more to settle. If it does not settle, the scan is repeated.
- Twist: Immediate surgery to untwist, with both testes stitched in place.
- Suspected growth: Urgent referral. Surgery through a groin cut, with blood markers taken first. A needle through the scrotum is deliberately avoided.
- Hernia: Surgical repair, urgently if it will not go back in.
Ultrasound is available on site, so most swellings can be sorted out the same day. Consultations are private.
What to Bring
- Any previous scrotal ultrasound reports and images.
- When you first noticed it, and whether it has changed size.
- Whether it hurts, and whether standing or lying makes a difference.
- Details of any previous hernia, scrotal or groin surgery.
- Recent urine reports, if there has been fever or burning.
- Semen reports, if fertility is part of the reason for coming.
This page provides general information only. It is not a substitute for medical advice, diagnosis or treatment. Consult a qualified urologist for assessment appropriate to your situation.