Prehn Sign

What is the Prehn sign?

A positive Prehn sign is symptomatic relief of scrotal pain with the gentle elevation of the affected hemiscrotum. Historically, a positive Prehn sign has been associated with epididymitis, whereas a lack of relief raises concern for testicular torsion.

Although it may contribute to the bedside assessment of acute scrotal pain, Prehn’s sign is not sufficiently sensitive to exclude testicular torsion on its own. The sign should be interpreted together with the history, scrotal examination, cremasteric reflex, and Doppler ultrasound when needed. If torsion is clinically suspected, urgent urologic evaluation should not be delayed.

What causes a positive Prehn sign?

The Prehn sign reflects the mechanical and physiological differences between inflammatory and ischemic conditions of the scrotum. In the context of epididymitis vs torsion, positive Prehn’s sign classically refers to pain relief with elevation of the affected hemiscrotum, a finding more consistent with epididymitis than with torsion. This physical relief is typically seen in epididymitis or epididymo-orchitis, where the tissues are swollen and inflamed but still perfused.

Conversely, testicular torsion involves a physical twisting of the spermatic cord that cuts off the blood supply. Because the primary issue is spermatic cord twisting with ischemia, scrotal elevation typically does not relieve the pain.

What are the signs and symptoms associated with the Prehn sign?

A positive Prehn sign usually aligns with clinical indicators of infection, such as fever, a gradual onset of pain, and urinary symptoms. These findings are common when a patient has underlying prostatitis or a sexually transmitted infection. If the scrotum is red, warm, and tender, and the pain lessens with elevation, an inflammatory cause such as epididymitis is highly probable.

In contrast, a negative Prehn sign is often found alongside “red flag” symptoms. These include an abrupt onset of agonizing pain, nausea, vomiting, and a “high-riding” testicle that sits horizontally in the scrotum. Furthermore, the absence of the cremasteric reflex (the testicle rising when the inner thigh is stroked) helps to increase suspicion for testicular torsion.

How is a Prehn sign identified?

To elicit the Prehn sign, the provider supports the affected side of the scrotum and gently lifts it toward the inguinal canal. The clinician then asks the patient if the pain has improved, stayed the same, or worsened. A decrease in pain confirms a positive Prehn sign, while persistent or increased pain is documented as a negative result.

The maneuver is most effective when performed early in the physical exam, providing immediate bedside data. If the diagnosis remains uncertain, color Doppler ultrasound can help evaluate testicular blood flow, but imaging should not delay surgical assessment when torsion is strongly suspected.

How is a Prehn sign treated?

Management depends on the overall clinical assessment and the suspected cause of the scrotal pain. A positive Prehn sign is more consistent with epididymitis or epididymo-orchitis, which is treated with targeted antibiotics to cover common pathogens. Supportive care involving scrotal elevation, ice packs, and anti-inflammatory medications helps relieve symptoms.

If the examination shows a negative Prehn sign, then testicular torsion should be strongly considered. In that case, the patient would require immediate urologic consultation. Torsion is a surgical emergency that usually requires operative detorsion and fixation within six hours to save the testicle. While a physician may attempt manual detorsion at the bedside to restore temporary flow, it is never a substitute for definitive surgical intervention.

What are the most important facts to know about the Prehn sign?

• A positive Prehn sign is symptomatic relief of scrotal pain with gentle elevation of the affected hemiscrotum.
• It may contribute to the bedside assessment of acute scrotal pain, helping differentiate between epididymitis and testicular torsion.
• Testicular torsion classically produces a negative Prehn sign, meaning pain is not relieved by elevation, but this finding alone cannot confirm the diagnosis.
• A negative Prehn sign with sudden pain and an absent cremasteric reflex should prompt immediate surgical evaluation for testicular torsion.
• Sudden scrotal pain with a high-riding testis, abnormal lie, or absent cremasteric reflex should prompt immediate urologic evaluation for torsion.
• Treatment is directed at the underlying diagnosis: epididymitis with a positive Prehn sign is usually treated medically, whereas suspected testicular torsion requires emergent surgical management.