Prehn's sign is a medical diagnostic indicator that was once believed to help determine whether the presenting testicular pain

Testicular pain

Testicular pain or scrotal pain is when part or all of either one or both testicles hurt. Pain of the scrotum is often included. It may be either acute, subacute or chronic depending on its duration. Causes rank from benign muscular skeletal problems to emergent condition such as Fournier's...

 is caused by acute epididymitis

Epididymitis

Epididymitis is a medical condition in which there is inflammation of the epididymis . This condition comprises gradual onset of testicular pain that can vary from mild to severe, and the scrotum may become red, warm and swollen...

 or from testicular torsion

Testicular torsion

Testicular torsion is when the spermatic cord to a testicle twists, cutting off the blood supply. The most common symptom is acute testicular pain and the most common underlying cause is a congenital malformation known as a "bell-clapper deformity". The diagnosis is often made clinically but if it...

. Although elevation of the scrotum when differentiating epididymitis from testicular torsion is of clinical value, Prehn's sign has been shown to be inferior to Doppler ultrasound to rule out testicular torsion.

According to Prehn's sign, the physical lifting of the testicles relieves the pain of epididymitis but not pain caused by testicular torsion.

• Negative Prehn's sign indicates no pain relief with lifting the affected testicle, which points towards testicular torsion which is a surgical emergency and must be relieved within 6 hours.

• Positive Prehn's sign indicates there is pain relief with lifting the affected testicle, which points towards epididymitis.