What causes orchitis?

Updated: Aug 16, 2017
  • Author: Nataisia Terry, MD; Chief Editor: Erik D Schraga, MD  more...
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Most commonly, mumps causes isolated orchitis. The onset of scrotal pain and edema is acute.

Because mumps orchitis is responsible for most cases of isolated orchitis, diagnosis in the ED usually is based on a reported history of a recent mumps infection or parotitis with a presentation of testicular edema.

Other rare viral etiologies include coxsackievirus, infectious mononucleosis, varicella, and echovirus. Some case reports have described mumps orchitis following immunization with the mumps, measles, and rubella (MMR) vaccine.

Bacterial causes usually spread from an associated epididymitis in sexually active men or men with BPH; bacteria include Neisseria gonorrhoeae, Chlamydia trachomatis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus and Streptococcus species. Bacterial orchitis rarely occurs without an associated epididymitis.

Immunocompromised patients have been reported to have orchitis with the following etiologic agents: Mycobacterium avium complex, Cryptococcus neoformans, Toxoplasma gondii, Haemophilus parainfluenzae, and Candida albicans.

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