Scrotal swelling: causes, when to seek urgent help and how it is assessed in the UK

The scrotum is the bag of skin that holds the testicles. Swelling can affect the whole scrotum or only one side, and it can come on suddenly or slowly. It may be painful or painless. The swelling can arise from the skin of the scrotum, from fluid around the testicle, from the epididymis behind it, from the testicle itself or from a hernia that extends down from the groin.

Because the causes range from minor to urgent, the practical question is how quickly you need to be seen. The NHS draws a clear line: sudden, unbearable pain is an emergency, while a lump, enlargement, heaviness or persistent ache needs a GP appointment without delay.

The table summarises causes described in NHS information, with the features that tend to go with each.

The NHS says to call 999 or go to A&E if you get sudden, unbearable pain in your testicles or tummy. This could be caused by the testicle becoming twisted and needs to be treated in hospital as soon as possible. The NHS advises not driving yourself to A&E: ask someone to drive you or call 999 for an ambulance, and take any medicines with you.

Do not wait to see if sudden severe pain eases, and do not assume it is an infection, particularly in teenagers and young men. Pain and swelling that come on over hours need the same urgent approach.

The NHS advises seeing a GP if you have a lump in your testicles, swollen testicles, a change in their shape, a change in the way they feel, one testicle becoming bigger than the other, or aching or discomfort that does not go away. Lumps can be a sign of testicular cancer, which is easier to treat if found early.

For testicular cancer symptoms, the NHS adds that the scrotum feeling heavy, firm or hard, or an ache in the testicle or scrotum, should be checked, and that these symptoms are common and can be caused by many conditions, so having them does not definitely mean cancer. The GP will ask about your symptoms and general health, check your testicles and the lymph nodes at the top of your legs, and may arrange an urgent referral if cancer is possible.

For suspected epididymitis, the NHS says you will usually need tests to find the cause, which may include a groin examination, a swab of the urethra to test for infection, urine and blood tests, and a rectal examination to check for problems with the prostate. Sexual health clinics can provide the same antibiotics as a GP, and many offer walk-in appointments.

If a lump is found, an ultrasound scan and blood tests are commonly arranged through urgent referral, and the specialist team decides next steps. Sexual partners may be offered testing if an infection is found.

The NHS says the usual treatment for epididymitis is antibiotics, given as injections or tablets, and it is important to finish the course. You should start to feel better within a few days, though it may take up to 3 months to recover fully, and further tests may be arranged if symptoms persist.

For pain and swelling the NHS suggests painkillers such as paracetamol or ibuprofen (check with a pharmacist if you have a history of seizures and are on certain antibiotics), a cold pack held on the groin, and underwear that supports the scrotum. It advises not having sex if you have gonorrhoea or chlamydia until you have finished treatment or for 7 days after. Treatment of other causes, such as a twisted testicle, cancer or a large hydrocele, is arranged by hospital specialists.

The NHS advises checking your testicles regularly so you know what is normal for you, which makes it easier to notice changes in size, look or feel. A new lump, a difference in size that is new, or a heavy or hard feeling should prompt an appointment rather than waiting.

NHS routes are GP, sexual health clinic, urgent referral for suspected cancer and emergency department for sudden severe pain. All are free at the point of use.

Some men choose a private urology consultation or scrotal ultrasound for convenience. This is reasonable for non-urgent swelling, but sudden severe pain should never wait for a private appointment. Keep your GP informed so any follow-up is coordinated.