Do Sexually Transmitted Infections (STIs) cause epididymitis?

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From the Guidelines

Yes, sexually transmitted infections (STIs) can cause epididymitis, particularly in men under 35 years of age, with Chlamydia trachomatis and Neisseria gonorrhoeae being the most common causes 1. Epididymitis is inflammation of the epididymis, the coiled tube at the back of the testicle that stores and carries sperm. In men under 35, STIs are the most common cause of epididymitis, and these infections typically spread from the urethra or bladder to the epididymis. The diagnosis of epididymitis caused by STIs can be made using nucleic acid amplification tests (NAATs), which are the most sensitive and rapid diagnostic procedure for these agents 1. Treatment usually involves antibiotics such as doxycycline (100mg twice daily for 10 days) for chlamydia or ceftriaxone (250mg intramuscular injection) plus doxycycline for gonorrhea. Pain management with NSAIDs, scrotal support, and rest are also recommended. Sexual partners should be notified and treated to prevent reinfection. In older men, epididymitis is more commonly caused by non-sexually transmitted bacteria from urinary tract infections or prostate infections, which can be diagnosed using culture and antimicrobial susceptibility testing 1. The inflammation occurs when bacteria travel from the urethra through the vas deferens to the epididymis, causing pain, swelling, and sometimes fever. Prompt treatment is important to prevent complications like abscess formation or reduced fertility. Key points to consider in the diagnosis and treatment of epididymitis include:

  • Age of the patient: men under 35 are more likely to have STIs as the cause of epididymitis, while older men are more likely to have non-sexually transmitted bacteria as the cause 1.
  • Symptoms: pain, swelling, and fever are common symptoms of epididymitis.
  • Diagnostic tests: NAATs are the most sensitive and rapid diagnostic procedure for STIs, while culture and antimicrobial susceptibility testing are used to diagnose non-sexually transmitted bacteria 1.
  • Treatment: antibiotics, pain management, and rest are recommended for the treatment of epididymitis.

From the Research

Causes of Epididymitis

  • Sexually transmitted infections (STIs) are a common cause of epididymitis, particularly in younger men 2, 3, 4, 5, 6.
  • The most common pathogens responsible for epididymitis in sexually active males are Neisseria gonorrhoeae and Chlamydia trachomatis 2, 3, 4, 5, 6.
  • In men older than 35 years, epididymitis is usually caused by enteric bacteria, such as Escherichia coli, which are transported by reflux of urine into the ejaculatory ducts secondary to bladder outlet obstruction 2, 3, 4, 5.

Demographic Factors

  • Men under 35 years of age are more likely to have epididymitis caused by STIs, with Chlamydia trachomatis being the most common pathogen in this age group 2, 3, 4, 5.
  • Men over 35 years of age are more likely to have epididymitis caused by enteric bacteria, such as Escherichia coli 2, 3, 4, 5.

Clinical Characteristics

  • Epididymitis typically presents with gradual onset of posterior scrotal pain, which may be accompanied by urinary symptoms such as dysuria and urinary frequency 2, 3.
  • Physical findings include a swollen and tender epididymis with the testis in an anatomically normal position 2, 3.
  • Laboratory tests, such as nucleic acid amplification testing (NAAT) for chlamydia and gonorrhea, and urinalysis and urine culture, can help diagnose the underlying cause of epididymitis 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Epididymitis: An Overview.

American family physician, 2016

Research

Epididymitis, orchitis, and related conditions.

Sexually transmitted diseases, 1984

Professional Medical Disclaimer

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.

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