What are the possible causes of a painful penis?

Causes of Painful Penis

Painful penis has multiple etiologies that must be rapidly differentiated based on anatomical location and age, with testicular torsion being the most critical emergency requiring surgical intervention within 6-8 hours, while epididymitis represents the most common cause in adults and sexually transmitted infections dominate in younger men under 35 years. 1, 2

Testicular and Scrotal Causes

Testicular Torsion (Surgical Emergency)

• Most critical diagnosis requiring immediate urological consultation and surgical exploration within 6-8 hours to prevent permanent testicular loss 1, 2
• Presents with abrupt onset of severe scrotal pain, more common in adolescents and postpubertal boys with bimodal distribution (neonates and adolescents) 1, 2
• Pain is NOT relieved with testicular elevation (negative Prehn sign), distinguishing it from epididymitis 2
• Duplex Doppler ultrasound shows decreased or absent blood flow to affected testicle and "whirlpool sign" of twisted spermatic cord 1, 2
• Critical pitfall: Normal urinalysis does NOT exclude testicular torsion 1, 2

Epididymitis/Epididymo-orchitis

• Most common cause of testicular pain in adults, representing approximately 600,000 cases annually in the United States 1
• Characterized by gradual onset of pain (versus abrupt in torsion), distinguishing feature from torsion 1, 2

Age-Based Etiology:

• Under 35 years or sexually active: Chlamydia trachomatis and Neisseria gonorrhoeae are primary pathogens 3, 4, 5
• Over 35 years: Gram-negative enteric organisms (especially E. coli) associated with urinary tract infections, bladder outflow obstruction, or recent urological instrumentation 3, 4, 6
• Men who are insertive partners during anal intercourse: sexually transmitted enteric organisms 3

Clinical Features:

• Unilateral testicular pain and tenderness with hydrocele and palpable epididymal swelling 3
• Usually accompanied by urethritis (often asymptomatic) in sexually transmitted cases 3
• Ultrasound shows enlarged epididymis with increased blood flow on color Doppler (opposite of torsion) 1, 7, 2
• Urethral Gram stain showing >5 polymorphonuclear leukocytes per oil immersion field supports diagnosis 3, 2

Treatment:

• For sexually transmitted epididymitis (age <35): Ceftriaxone 250 mg IM single dose PLUS Doxycycline 100 mg orally twice daily for 10 days 3, 2
• For enteric organisms (age >35 or urinary tract pathology): Ofloxacin 300 mg orally twice daily for 10 days OR Levofloxacin 500 mg orally once daily for 10 days 3
• Adjunctive therapy: bed rest, scrotal elevation, and analgesics until fever and inflammation subside 3, 7
• Failure to improve within 3 days requires reevaluation of diagnosis and therapy 3, 7

Torsion of Testicular Appendage

• Most common cause of testicular pain in prepubertal boys 1, 2
• Presents with tender nodule and "blue dot sign" (pathognomonic but only seen in 21% of cases) 1, 2
• Ultrasound shows normal testicular perfusion with localized hyperemia near the appendage 1

Orchitis

• Less common than epididymitis, usually blood-borne dissemination 5
• Mumps is the most frequent cause of viral orchitis 5
• Pyogenic orchitis usually results from extension of epididymal inflammation 5

Penile Shaft and Glans Causes

Balanitis/Balanoposthitis

• Inflammation of glans penis (balanitis) often involving prepuce (balanoposthitis) 8, 9
• Candida species are the most frequently isolated microorganisms in infectious balanitis 9
• Other infectious causes: Staphylococcus spp., Groups B and D Streptococci, anaerobic bacteria, viral infections, parasites, and sexually transmitted infections 8, 9
• Non-infectious causes: lichen planus, psoriasis, contact dermatitis 8
• Clinical aspect is of little value in predicting the infectious agent, requiring culture studies 9
• Management: treat infections, keep glans dry, ensure balanced genital hygiene; therapeutic circumcision as last resort for chronic cases 8

Lichen Sclerosus (Male Genital)

• Common sites: prepuce, coronal sulcus, glans penis, rarely penile shaft 3
• Presenting complaint usually tightening of foreskin leading to phimosis, causing erectile dysfunction and painful erections 3
• 30% of adult phimosis is due to lichen sclerosus 3
• Perimeatal involvement may lead to stenosis and urinary obstruction 3
• Squamous cell carcinoma can develop, particularly in chronic cases 3

Urethral Causes

Urethritis

• Usually accompanies sexually transmitted epididymitis, often asymptomatic 3
• Diagnosed by urethral Gram stain showing >5 polymorphonuclear leukocytes per oil immersion field 3
• Requires nucleic acid amplification testing for N. gonorrhoeae and C. trachomatis 3

Critical Diagnostic Algorithm

Immediate Assessment:

1. Determine onset of pain: Abrupt = torsion until proven otherwise; Gradual = epididymitis more likely 1, 2
2. Age stratification: Adolescents = high torsion risk; Adults >25 years = epididymitis more likely 1, 2
3. Prehn sign: Pain NOT relieved with elevation suggests torsion 2
4. Urinalysis: Obtain immediately, but normal result does NOT exclude torsion 1, 2

Imaging:

• Duplex Doppler ultrasound is first-line imaging with sensitivity 69-96.8% and specificity 87-100% for torsion 1, 2
• When clinical suspicion for torsion is high, proceed directly to surgical exploration without waiting for imaging 1, 2

Management Priority:

• Any acute scrotal pain must be treated as potential surgical emergency until torsion is excluded 1, 2
• Testicular viability is compromised if surgical intervention delayed beyond 6-8 hours 1, 2