What causes severe scrotal and penile edema?

Causes of Severe Scrotal and Penile Edema

Severe scrotal and penile edema has multiple etiologies that must be systematically evaluated, with the most critical being to rule out testicular torsion as a surgical emergency, followed by infectious causes (epididymitis/epididymo-orchitis), inflammatory bowel disease manifestations, fluid overload states, and idiopathic conditions.

Life-Threatening and Urgent Causes

Testicular Torsion with Secondary Edema

• Testicular torsion presents with sudden onset of severe scrotal pain and swelling, requiring surgical intervention within 6-8 hours to prevent testicular loss 1
• The condition is more common in adolescents with a bimodal distribution peaking in neonates and postpubertal boys 1
• Scrotal edema develops secondary to venous and lymphatic obstruction from the twisted spermatic cord 1
• Emergency Doppler ultrasound shows decreased or absent blood flow to the affected testicle and the pathognomonic "whirlpool sign" of the twisted spermatic cord 1
• Critical pitfall: Normal urinalysis does not exclude testicular torsion 1

Infectious Epididymitis/Epididymo-Orchitis

• Epididymitis is the most common cause of acute scrotal swelling in men younger than 35 years of age, typically caused by Chlamydia trachomatis or Neisseria gonorrhoeae 2
• The condition presents with more gradual onset of pain compared to torsion, with scrotal elevation providing relief (positive Prehn sign) 3
• Doppler ultrasound demonstrates an enlarged epididymis with increased blood flow 1
• Treatment requires ceftriaxone 250 mg IM single dose PLUS doxycycline 100 mg orally twice daily for 10 days for sexually transmitted causes 4
• For enteric organisms or antibiotic allergies, ofloxacin 300 mg orally twice daily for 10 days is recommended 4
• Adjunctive therapy includes bed rest, scrotal elevation, and analgesics until fever and inflammation subside 4
• Failure to improve within 3 days mandates reevaluation for abscess, infarction, testicular cancer, or tuberculous/fungal epididymitis 4

Systemic and Inflammatory Causes

Crohn's Disease (Metastatic Crohn's Disease)

• Penile and scrotal swelling can occur as an extraintestinal manifestation of Crohn's disease, representing an uncommon form of metastatic Crohn's disease 5
• In 88% of pediatric cases, cutaneous genital symptoms precede the formal diagnosis of Crohn's disease, with some patients having no gastrointestinal symptoms at initial presentation 5
• This diagnosis should be considered in all patients with unexplained genital swelling, particularly in boys ages 7-16 years 5
• Treatment of the underlying Crohn's disease with systemic medications (average 3.4 medications including topical and systemic agents) is most effective 5

Fluid Overload States

• Post-paracentesis scrotal edema can develop within 12 hours after abdominal paracentesis in patients with decompensated liver cirrhosis and ascites 6
• The mechanism involves a fistula tract forming between the peritoneal cavity and Camper's and Scarpa's fascia, allowing fluid to collect in the scrotum 6
• Treatment consists of conservative management with oral diuretics and scrotal elevation, with significant improvement typically seen within 2 days 6
• Consider this diagnosis in any patient with cirrhosis, ascites, or recent paracentesis presenting with acute scrotal swelling 6

Benign and Self-Limited Causes

Acute Idiopathic Scrotal Edema

• Acute idiopathic scrotal edema is a rare, self-limiting condition primarily affecting prepubertal boys but can occur in adults, characterized by painless or minimally painful marked scrotal wall thickening 1
• The condition is a diagnosis of exclusion after ruling out testicular torsion, epididymitis, and other surgical emergencies 1
• The edema is produced by subcutaneous swelling with a normal testis and cord on examination 7
• A localized allergic phenomenon, possibly a local form of angioneurotic edema, appears to be the most likely etiology 7
• No connection with trauma, periurethral disease, or streptococcal disease has been established 7

Hydrocele

• Hydrocele presents as a fluid collection around the testis that demonstrates complete transillumination 8
• While typically not causing severe edema, large or tense hydroceles can contribute to scrotal swelling 8
• Critical pitfall: Hydroceles can occasionally mask underlying testicular tumors, particularly in young men 8

Rare Infectious Causes

Lymphogranuloma Venereum (LGV)

• LGV caused by Chlamydia trachomatis serovares L1, L2, or L3 manifests most frequently in heterosexual men as painful inguinal and/or femoral lymphadenopathy that is usually unilateral 3
• This can lead to secondary scrotal and penile edema through lymphatic obstruction 3

Erysipelatous Edema

• Acute erysipelatous edema of the scrotum represents a rare infectious/inflammatory cause with unknown etiology 9
• Treatment options include compression bandaging, though the condition may persist despite interventions 9

Diagnostic Algorithm

When evaluating severe scrotal and penile edema:

1. Immediate assessment for testicular torsion: Sudden onset, severe pain, negative Prehn sign → urgent Doppler ultrasound and surgical consultation 1

2. If torsion excluded, evaluate for infection: Gradual onset, positive Prehn sign, fever, urethral discharge → urinalysis, urethral swab for gonorrhea/chlamydia, and empiric antibiotics 4, 2

3. Consider systemic causes: History of inflammatory bowel disease symptoms, recent paracentesis, liver disease with ascites 5, 6

4. Rule out malignancy: Palpable mass, lack of transillumination, persistent swelling after antimicrobial therapy → ultrasound and possible biopsy 4, 8

5. Diagnosis of exclusion: If all above are negative and patient has minimal pain with marked scrotal wall thickening → acute idiopathic scrotal edema 1, 7