Often unilateral scrotal pain, swelling and erythema of relatively acute onset.

Patients may complain of symptoms or urethritis or urethral discharge, but these symptoms may be absent. In addition, there may be symptoms in keeping with a urinary tract infection such as fever, dysuria, frequency and urgency.

Testicular torsion is the most important differential diagnosis. This is a surgical emergency that should be considered first in all patients, particularly young men, as testicular salvage is required within six hours and success diminishes with time. The pain is typically sudden, occurring within hours and usually severe. The pain can radiate into the groin or lower abdomen and associated with nausea and vomiting. If there is any doubt as to the cause of an acutely painful and swollen testes, torsion should be considered until proven otherwise.

• Tenderness to palpation on the affected side.
• Palpable swelling of the epididymis, with or without involvement of the testicle.
• There may also be urethral discharge, secondary hydrocoele, erythema and/or oedema of the scrotum on the affected side, pyrexia.

More often seen on patients with uropathogen-related epididymo-orchitis.

• Reactive hydrocele.
• Abscess formation and infarction of the testicle – these are rare complications.
• Infertility- there is a poorly understood relationship between epididymo-orchitis and infertility.