What are the causes of a swollen testicle (orchitis or epididymitis)?

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Last updated: May 20, 2025 • View editorial policy

Differential Diagnosis for Swollen Testicule

  • Single most likely diagnosis + Epididymitis: This is the most common cause of a swollen testicle, typically resulting from a bacterial infection, often related to a urinary tract infection or sexually transmitted infection.
  • Other Likely diagnoses + Orchitis: Inflammation of the testicle, often caused by viral or bacterial infections, which can lead to swelling and pain. + Hydrocele: A collection of fluid around the testicle, causing swelling, which can be primary (idiopathic) or secondary to trauma, infection, or tumor. + Varicocele: Enlargement of the veins within the scrotum, similar to varicose veins, which can cause swelling and discomfort.
  • Do Not Miss (ddxs that may not be likely, but would be deadly if missed.) + Testicular torsion: A medical emergency where the spermatic cord becomes twisted, cutting off blood supply to the testicle, requiring immediate surgical intervention to save the testicle. + Testicular cancer: Although less common, testicular cancer can present with swelling, and early detection is crucial for effective treatment and prognosis.
  • Rare diagnoses + Spermatocele: A cystic structure filled with sperm, which can cause swelling but is usually painless and benign. + Hematocele: A collection of blood within the scrotum, often resulting from trauma, which can cause swelling and pain. + Filariasis: A parasitic infection that can cause swelling and inflammation of the scrotum, more common in tropical regions.

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.