Single most likely diagnosis
- Epididymitis: This is the most common cause of a swollen testicle, especially in young men. It is usually caused by a bacterial infection, such as chlamydia or gonorrhea, and is characterized by pain, swelling, and redness of the testicle.
Other Likely diagnoses
- Orchitis: This is an inflammation of the testicle, often caused by a viral infection, such as mumps. It can also be caused by bacterial infections, such as epididymitis.
- Testicular torsion: This is a twisting of the spermatic cord, which can cut off the blood supply to the testicle. It is a medical emergency and requires prompt treatment.
- Hydrocele: This is a collection of fluid around the testicle, which can cause swelling.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Testicular cancer: Although rare, testicular cancer can cause a swollen testicle. It is essential to rule out this diagnosis, especially in men with a family history or other risk factors.
- Spermatic cord torsion with necrosis: If left untreated, testicular torsion can lead to necrosis of the testicle, which can be deadly.
Rare diagnoses
- Henoch-Schönlein purpura: This is a rare condition that can cause inflammation and swelling of the testicle, as well as other symptoms such as joint pain and rash.
- Filariasis: This is a parasitic infection that can cause swelling and inflammation of the testicle, although it is rare in developed countries.