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Prehn’s Sign

What Is It, Associated Conditions, and More

Author: Lily Guo

Editors: Ahaana Singh, Ian Mannarino, MD, MBA

Illustrator: Jillian Dunbar


What is Prehn’s sign?

Prehn's sign is a clinical finding that helps clinicians determine whether testicular pain is caused by epididymitis or testicular torsion. A positive Prehn's sign, characterized by pain relief from the maneuver, is indicative of epididymitis, or the inflammation of the epididymis (a duct running behind the testes). Conversely, a negative Prehn's sign is characterized by an exacerbation of pain and indicates testicular torsion, or the rotation of the testicles around the spermatic cord, resulting in the obstruction of blood flow to the testicle. Testicular torsion is considered a medical emergency and requires immediate medical attention. 

How is Prehn’s sign performed?

Prehn's sign is performed by a clinician lifting one half of the scrotum, which is the sack of skin containing the testicles, blood vessels, and spermatic cord. They then assess for consequent changes in pain levels experienced in the testicles.

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What conditions are associated with a negative Prehn’s sign?

A negative Prehn's sign, or exacerbation of pain upon elevation of the testicle, is one of the clinical features of testicular torsion. This occurs when the testicle rotates and compresses the spermatic cord (a bundle of fibers and tissue running from the abdomen to the testicles). Within the spermatic cord are the vessels that supply blood to the testes, and a sudden reduction in blood flow due to compression may lead to severe pain, swelling, and eventually necrosis, or tissue death. Testicular torsion usually has a sudden onset of acute scrotal pain which can radiate to the lower abdomen. Individuals may also experience nausea and vomiting. 

Another way to diagnose testicular torsion is by checking for the cremasteric reflex by pinching or stroking the inner thigh on the affected side. Normally, this reflex causes the testicle to contract and rise, but it is often absent in individuals with testicular torsion. Additional tests that may be performed include urine analysis, as well as ultrasound imaging of the scrotum. In order to treat testicular torsion, a provider may use a manual detorsion technique by manually twisting the testicle outward and laterally, away from the body, which should relieve the pain and lead to increased blood flow. If increased pain is felt, the clinician can try rotating in the opposite direction. If the blood supply is cut off for too long, the tissue may become severely damaged and the testicle may need to be removed. In these situations, emergency surgery is often required. 

What conditions are associated with a positive Prehn’s sign?

A positive Prehn's sign, or relief of pain upon elevation of the scrotum, is associated with acute or chronic epididymitis. The epididymis is a duct that carries and stores sperm and it can become susceptible to bacterial infection. If this occurs, there may be painful swelling and inflammation of the scrotum. An infection that lasts for less than six weeks is known as acute epididymitis; infections lasting more than six weeks are considered to be chronic. 

Epididymitis is usually a result of sexually transmitted infections, such as gonorrhea and chlamydia. Other symptoms include fever, increased need to urinate, and pain upon urination. Unlike testicular torsion, the onset of testicular pain with epididymitis is gradual. Diagnosis typically involves urine testing and ultrasound imaging of the scrotum. In order to treat the associated infection, an antibiotic may be prescribed. In addition, anti-inflammatory medications may be used to control pain and reduce symptoms. 

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

Prehn's sign is an evaluation used to determine the cause of testicular pain. It is performed by lifting the scrotum and assessing the consequent changes in pain. A positive Prehn's sign indicates relief of pain upon elevation of the scrotum and is associated with epididymitis. Epididymitis can be caused by bacterial infection of the epididymis and can usually be treated with a course of antibiotics. On the other hand, a negative Prehn's sign indicates exacerbation of acute pain associated with testicular torsion. Testicular torsion leads to sudden acute scrotal pain due to the spermatic cord rotating and cutting off its blood supply. This is considered a medical emergency and requires immediate diagnosis and treatment.

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Related links

Anatomy and physiology of the male reproductive system
Epididymitis
Testicular torsion

Resources for research and reference

Acute Scrotal Pain. (2013). American Family Physician, 42(11): 790–792. Retrieved November 25, 2020, from https://www.racgp.org.au/afp/2013/november/acute-scrotal-pain/

Epididymitis. (2019). In Mayo Clinic. Retrieved November 25, 2020, from https://www.mayoclinic.org/diseases-conditions/epididymitis/symptoms-causes/syc-20363853

Epididymitis Diagnosis and Tests. (n.d.). In Cleveland Clinic. Retrieved November 26, 2020, from https://my.clevelandclinic.org/health/diseases/17697-epididymitis/diagnosis-and-tests

Roth, B., Giannakis, I., Ricklin, M. E., Thalmann, G. N., & Exadaktylos, A. K. (2018). An Accurate Diagnostic Pathway Helps to Correctly Distinguish Between the Possible Causes of Acute Scrotum. Oman Medical Journal, 33(1): 55–60. DOI: 10.5001/omj.2018.10

Saxena, A. K. (2016). Manual Detorsion of the Testes. In MedScape. Retrieved December 25, 2020, from https://emedicine.medscape.com/article/1413565-overview

Testicular torsion. (2020). In Mayo Clinic. Retrieved November 25, 2020, from https://www.mayoclinic.org/diseases-conditions/testicular-torsion/symptoms-causes/syc-20378270