Orchitis: symptoms, causes, treatment and when it is an emergency

BASHH says epididymo-orchitis causes pain and swelling inside the scrotum, usually on one side, and some people also have pain when peeing, a discharge from the urethra or a fever. The NHS epididymitis page lists sudden or gradual pain in one or both testicles, a tender, warm, swollen scrotum, and a build-up of fluid around the testicle (hydrocele) that feels like a lump or swelling.

Depending on the cause there may be other symptoms, such as difficulty peeing or a white, yellow or green discharge from the tip of the penis. NHS Borders guidance says onset is usually over days, with localised tenderness at the epididymis.

Testicular torsion, where the testicle twists in the scrotum, causes similar pain and swelling in young people. BASHH says it causes sudden onset severe pain and swelling and may result in long-term damage to the testicle if not dealt with quickly, and that anyone with concern about it is referred immediately to the emergency department or urology team.

NICE CKS says testicular torsion should be suspected in any person presenting with acute scrotal pain and/or swelling before other causes are considered. NHS Borders advises that a sudden onset of a painful swollen testicle in a young man is torsion until proven otherwise, and a surgical emergency.

• Sudden, severe, unbearable pain in a testicle or the tummy: call 999 or go to A&E (NHS).

• Do not drive yourself to A&E; ask someone to drive you or call 999.

• Do not wait to see whether it settles.

BASHH says that in people under 35 the most common cause is a sexually transmitted infection such as chlamydia or gonorrhoea, and in people over 35 it is a urine infection. Occasionally it is due to a gut bacterial infection from penetrative anal sex, and rarely to infections such as mumps or tuberculosis.

The NHS adds that a UTI is more likely if you have an enlarged prostate, a urinary catheter or recent groin, prostate or bladder surgery, and that less common causes include mumps, tuberculosis, the heart-rhythm medicine amiodarone, groin injury and Behcet's disease.

The NHS lists swollen testicles (orchitis) among the complications of mumps, along with swollen ovaries, meningitis, pancreatitis and temporary hearing loss in one ear. These are more likely if you get mumps as a teenager or adult, but they usually do not cause serious long-term problems.

NHS Borders guidance says 20 to 25% of adult males with mumps will develop orchitis, about a week after the initial symptoms. The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you or your child have mumps and have painful or swollen testicles, or tummy or back pain. Two doses of the MMR vaccine make mumps very unlikely.

BASHH says epididymo-orchitis is usually diagnosed on the day and treatment started: it is easily treated with antibiotics, painkillers and rest, though the pain frequently takes weeks to months to settle. The NHS says antibiotics may be injections, tablets or both, and you should finish the whole course even if you feel better.

Supportive underwear or scrotal support may help ease the pain and swelling, according to BASHH, and the NHS also suggests a cold pack or frozen peas wrapped in a tea towel on the groin. If symptoms get worse or do not improve within 3 days, BASHH says to re-attend the clinic or seek further medical advice. Mumps is a viral infection, and the NHS advice for mumps is rest, plenty of fluids and paracetamol or ibuprofen for pain and swelling.

The NHS says you should start to feel better within a few days of starting antibiotics, but it may take up to 3 months to fully recover, and if you still have symptoms after that you might be referred for further tests. BASHH similarly says the pain frequently takes weeks to months to completely settle.

Left untreated, BASHH says epididymo-orchitis can result in continued pain and swelling, fluid around the testicle, a collection of pus in the scrotum and, very rarely, shrinkage of the testicle and loss of fertility. Prompt, early treatment significantly reduces the likelihood of these complications.

BASHH says a health professional may examine your penis and scrotum and take urine tests, blood tests and a swab from the urethra, and recommends routine tests for chlamydia, gonorrhoea, syphilis and HIV. The NHS adds that a rectal examination may be done to check the prostate.

NICE CKS says an urgent ultrasound of the scrotum is arranged when there is diagnostic uncertainty or unexplained symptoms. The NHS says a lump in the testicles needs to be checked because it can be a sign of testicular cancer, which is easier to treat if found early.

BASHH says that if you have been diagnosed with an STI, sexual partners from the preceding 2 to 4 weeks need a full sexual health screen, and that it is best not to have sex until you have completed treatment and your partner has been tested. The NHS says partners from the past 6 months may be tested if an STI is found, and not to have sex for 7 days after finishing treatment for gonorrhoea or chlamydia.

MMR vaccination protects against mumps. Condoms reduce the risk of sexually transmitted infections.

The NHS says you can get treatment for epididymitis at a GP surgery or a sexual health clinic, many of which have walk-in services. BASHH says treatment at sexual health clinics is free. Emergency departments and urology teams manage suspected torsion.

Private urology and sexual health clinics can also assess and treat, and scrotal ultrasound is available privately, but the key step is the same: same-day assessment so that torsion is not missed.