Epididymitis is usually caused by an infection or irritation of the small coiled tube behind the testicle (the epididymis), most often from bacteria that travel from the urethra, bladder, or prostate.

What Causes Epididymitis?

1. The Basic Idea

Epididymitis means inflammation of the epididymis, the tube that stores and carries sperm behind each testicle.

Most cases are due to a bacterial infection that starts elsewhere in the urinary or genital tract and then spreads to the epididymis.

2. Main Medical Causes

Sexually transmitted infections (STIs)

In younger, sexually active men, STIs are the top cause.

  • Chlamydia
  • Gonorrhea

These bacteria usually start in the urethra (the tube you pee through) and can travel backward to the epididymis.

Urinary or prostate infections

In men over about 35, non‑sexual infections are more common causes.

  • Urinary tract infections (UTIs), especially with E. coli and other gut bacteria
  • Prostatitis (infection/inflammation of the prostate)

The bacteria can move from the bladder or prostate into the vas deferens and then the epididymis.

Viral infections

  • Mumps virus can sometimes inflame the testicle and epididymis, especially in unvaccinated people.

3. Non‑infectious / Mechanical Causes

Not all epididymitis is due to germs.

  • Chemical irritation: Urine flowing backward (reflux) into the epididymis can irritate it, sometimes after heavy lifting or straining.
  • Trauma/injury: A direct blow or repetitive strain (certain sports, a lot of running/jumping) can trigger inflammation.
  • Drug‑related: Some medications have been linked to epididymitis as a rare side effect (for example, certain heart medications), though this is less common.
  • Tuberculosis: TB infection can rarely involve the epididymis, especially in areas where TB is more common.

4. Age and Risk Patterns

Different age groups tend to have different typical causes.

  • Teen/young adult (roughly 19–35):
    • More likely: STIs (chlamydia, gonorrhea)
* Consideration of sexual abuse if occurring before sexual maturity.
  • Men over 35:
    • More likely: urinary tract or prostate infections, E. coli and similar bacteria.
  • Children and early teens:
    • More often: inflammation from trauma or repetitive activity, or urinary infection; infection still possible but STIs are less common and raise concern for abuse.

Other risk factors include:

  • Recent urinary tract surgery or catheter use
  • Structural problems in the urinary tract
  • Unprotected sex with new or multiple partners
  • History of UTIs or prostatitis

5. Is It Contagious?

  • The infection causing epididymitis (like chlamydia or gonorrhea) can be sexually transmitted, but the inflammation itself isn’t “caught” by another person.
  • Partners may need STI testing and treatment if an STI is found.

6. Quick FAQ-Style Table

[9][5][7][1][3] [9][5][7][3] [3] [1][3] [1][3]
Situation Most likely cause
Man under 35, new sexual partner, burning with urination STI such as chlamydia or gonorrhea spreading to the epididymis
Man over 35 with urinary symptoms and enlarged prostate Urinary or prostate infection with E. coli or similar bacteria
Boy with recent sports injury to the groin Inflammatory epididymitis from trauma or repetitive activity
Person with recent heavy lifting and sudden scrotal pain Possible urine reflux causing chemical irritation
Person with history of TB, chronic scrotal swelling Tuberculous epididymitis (rare)

7. When to Get Help (Important)

You should seek urgent medical care if you have:

  • Sudden or severe testicle or scrotal pain
  • Swelling, redness, or warmth in the scrotum
  • Fever, chills, feeling very unwell
  • Pain with urination, blood in urine, or discharge from the penis

Testicular torsion (a twisted testicle) can mimic epididymitis and is an emergency, especially in younger males, so doctors often treat sudden pain as urgent.

Information gathered from public forums or data available on the internet and portrayed here.