From the Guidelines
The most common causes of epididymitis are bacterial infections, specifically Chlamydia trachomatis and Neisseria gonorrhoeae in men under 35, and enteric bacteria such as E. coli in men over 35. In men under 35, sexually transmitted infections like Chlamydia trachomatis and Neisseria gonorrhoeae are the predominant causes, while in men over 35, enteric bacteria such as E. coli are more common, often associated with urinary tract infections or prostate issues 1. The infection spreads to the epididymis either through the vas deferens from the urethra or prostate, or via the bloodstream. Some key points to consider include:
- Sexually transmitted epididymitis usually is accompanied by urethritis, which often is asymptomatic 1
- Nonsexually transmitted epididymitis that is associated with urinary-tract infections caused by Gram-negative enteric organisms occurs more frequently among men aged >35 years, men who have recently undergone urinary-tract instrumentation or surgery, and men who have anatomical abnormalities of the urinary tract 1
- Proper diagnosis often requires urine cultures and STI testing to identify the specific pathogen and guide appropriate antibiotic therapy. Treatment typically involves antibiotics tailored to the likely pathogen: doxycycline 100mg twice daily for 10 days plus ceftriaxone 250mg as a single intramuscular dose for younger men with suspected STIs, or fluoroquinolones like ciprofloxacin 500mg twice daily for 10-14 days for older men with suspected enteric infections. Non-infectious causes include trauma, autoimmune conditions, and certain medications.
From the Research
Causes of Epididymitis
The causes of epididymitis can be categorized based on age and other factors.
- In children younger than 14 years, reflux of urine into the ejaculatory ducts is considered the most common cause of epididymitis 2.
- In sexually active males 14 to 35 years of age, Neisseria gonorrhoeae and Chlamydia trachomatis are the most common pathogens 2, 3, 4.
- In men who practice insertive anal intercourse, an enteric organism is also likely to be the cause 2.
- In men older than 35 years, epididymitis is usually caused by enteric bacteria transported by reflux of urine into the ejaculatory ducts secondary to bladder outlet obstruction 2.
- Coliform bacteria are the primary pathogens in other age groups 4.
- Sexually transmitted infections (STIs) are common in men <35 years of age diagnosed with epididymitis, orchitis, or both, with chlamydia being most common 5.
- E. coli was the most common bacteria growing in urine culture 5.
Bacterial Causes
The most common bacterial causes of epididymitis include: