What is the recommended treatment for cellulitis of the penis?

Treatment of Penile Cellulitis

For cellulitis of the penis, initiate treatment with antibiotics active against beta-hemolytic streptococci, specifically penicillin or amoxicillin, as streptococci (particularly Group B streptococci) are the primary causative organisms in this anatomical location. 1, 2

Pathogen-Specific Considerations

• Penile cellulitis is predominantly caused by beta-hemolytic streptococci, with Group B streptococci being the most common isolate in this specific anatomical location 1, 2
• Unlike cellulitis in other body regions, Staphylococcus aureus is less frequently involved unless there is penetrating trauma or an underlying abscess 3, 4
• The infection typically occurs without a discernible portal of entry, though it may follow sexual intercourse in young, sexually active men 1, 2

Treatment Algorithm by Severity

Mild to Moderate Cases (Outpatient Management)

First-line antibiotic options for 5 days: 3, 5

• Penicillin (oral or parenteral depending on severity) - this is the treatment of choice given the streptococcal etiology 6, 1
• Amoxicillin - equally effective alternative 3, 5
• Dicloxacillin or cephalexin - if broader coverage desired for potential MSSA 6, 3

For penicillin-allergic patients: 6, 3

• Clindamycin - preferred alternative with 99.5% susceptibility for streptococci 6
• Erythromycin - though increasing resistance noted (8-9% in recent surveillance) 6

Severe Cases or Systemic Symptoms

Indications for hospitalization and parenteral therapy: 5

• Rapid progression with intense swelling
• Systemic signs of infection (fever, elevated white blood cell count)
• Concern for deeper tissue involvement or necrotizing infection
• Immunocompromised status

Parenteral treatment options: 6

• Intravenous penicillin - remains first-line for severe streptococcal cellulitis 6
• Ampicillin-sulbactam or piperacillin-tazobactam - if broader coverage needed 6
• Vancomycin - only if MRSA suspected based on specific risk factors (injection drug use, known MRSA colonization, purulent drainage) 3

Critical Surgical Considerations

Immediate surgical decompression is required if: 1

• Fluid accumulates rapidly between Colles' and Buck's fascia causing intense swelling
• Failure to decompress this closed compartment with linear incisions will lead to devascularization and skin gangrene 1
• If gangrene develops, radical debridement of necrotic tissue plus a wide margin of adjacent inflamed skin must be performed 1

Treatment Duration and Monitoring

• Standard duration: 5 days with extension only if no clinical improvement is evident 3, 5
• Longer courses (7-14 days) reserved for severe cases with systemic involvement 3
• Monitor for clinical response within 48-72 hours; failure to improve should prompt consideration of resistant organisms or alternative diagnoses 4

Adjunctive Measures

• Elevation of the affected area to promote drainage of edema 3, 5
• Exclude sexually transmitted infections in young, sexually active men as part of the differential diagnosis 2
• Blood cultures are not routinely needed for typical cases but should be obtained if severe systemic features, immunocompromise, or neutropenia present 5

Common Pitfalls to Avoid

• Do not empirically cover MRSA in typical penile cellulitis without specific risk factors, as this represents overtreatment given the streptococcal predominance 3, 4
• Do not delay surgical decompression if rapid swelling occurs in the closed fascial compartments of the penis and scrotum, as this leads to irreversible skin necrosis 1
• Do not use fluoroquinolones as first-line therapy - they are inadequate for streptococcal coverage and should be reserved for penicillin-allergic patients only 6, 3
• Do not routinely obtain cultures from skin aspirates or blood in uncomplicated cases, as yield is extremely low (<5% for blood cultures, 15-20% for aspirates) 5, 4