Epididymitis is the inflammation of the epididymis and is commonly associated with genitourinary tract infections. Epididymitis is a clinical diagnosis, with patients typically presenting with a gradual onset of pain and swelling of the affected scrotum and a positive . Urinalysis and testing for sexually transmitted infections (STIs) can help confirm the diagnosis. Testicular torsion is the most important differential diagnosis of epididymitis; if it cannot be ruled out clinically, an urgent ultrasound must be performed. The treatment for epididymitis includes empiric antibiotic therapy based on the most likely source of infection and symptomatic management, e.g., scrotal elevation and NSAIDs.
Acute epididymitis: an inflammation of the epididymis, usually as a result of an infection
- Urinary tract infections
- Sexually transmitted infections
- Chronic epididymitis (> 6-week course of the disease)
- Unilateral scrotal pain and swelling; , which develops over several days and radiates to the ipsilateral flank 
- Tenderness along the posterior testis
- Positive Prehn sign: reduced pain when the affected hemiscrotum is elevated
- Scrotal skin overlying the epididymis may appear red, shiny, and edematous
- Low-grade fever (especially among children)
- Symptoms of lower urinary tract infection (e.g., dysuria, frequency, urgency), including urethritis (urethral discharge)
- Chronic epididymitis
The following recommendations are consistent with the 2021 CDC guidelines. 
- Epididymitis is a .
- Urine and urethral studies help tailor antibiotic therapy and identify the causative organism.
- Imaging is primarily used to rule out testicular torsion but can confirm epididymitis if the diagnosis is uncertain.
Testicular torsion is the most important differential diagnosis of epididymitis and must be ruled out first! Consult urology if the diagnosis remains unclear.
Routine laboratory studies 
- Urinalysis: to identify pyuria and/or bacteriuria
- Urine culture: to identify the causative organism and assess for antibiotic resistance 
- Nucleic acid amplification testing (NAAT) for Chlamydia trachomatis and Neisseria gonorrhea; (urine sample or urethral swab) 
- Gram stain of urethral secretions: to identify urethritis and gonococcal infections
Additional laboratory studies
Not usually indicated
- Nonspecific elevated acute phase reactants, e.g., leukocytosis, ↑ ESR, ↑ CRP may be present. 
- In patients with persistent clinical features despite antibiotic treatment, consider testing for alternate diagnoses, e.g., neoplasms, abscess, infarction, fungal organisms. 
- Consider chronic epididymitis and recent TB exposure.  in patients with
Duplex ultrasound of the scrotum 
- Testicular torsion
- See “.”
The differential diagnoses listed here are not exhaustive.
- Indicated for all patients with acute epididymitis
- Start empiric antibiotic treatment based on the most likely causative organism. 
- Patients with a suspected UTI source; (e.g., enteric organisms): fluoroquinolone, e.g., levofloxacin 
- Patients with a suspected STI source (e.g., chlamydia or gonorrhea): ceftriaxone PLUS doxycycline
- Patients who practice insertive anal sex: Cover both STIs and enteric organisms, e.g., ceftriaxone PLUS levofloxacin .
- Adjust antibiotic therapy once the causative organism is identified.
- If symptoms do not improve within 72 hours after starting treatment, reconsider other diagnoses.
If an STI is suspected, patients should abstain from sex until they and any partners have been successfully treated. Refer all sexual partners from the previous 60 days before symptom onset for evaluation, testing, and presumptive treatment. 
Indicated for all patients as needed
- Scrotal elevation
- Avoidance of aggravating activities
- Application of a cold pack
- Not generally indicated
- Exceptions include intrascrotal abscesses and some cases of chronic epididymitis