What oral antibiotic regimen is recommended for mild superficial cellulitis over an abdominoplasty wound when deep infection has been excluded, including options for penicillin allergy and community‑acquired MRSA risk?

Antibiotic Regimen for Mild Superficial Cellulitis Over Abdominoplasty Wound

For mild superficial cellulitis overlying an abdominoplasty wound with no deep infection, prescribe cephalexin 500 mg orally every 6 hours or dicloxacillin 250–500 mg orally every 6 hours for 5 days, extending only if warmth, tenderness, or erythema have not improved. 1, 2

First-Line Beta-Lactam Monotherapy

• Beta-lactam monotherapy achieves 96% clinical success in typical non-purulent cellulitis because the primary pathogens are beta-hemolytic streptococci (especially Streptococcus pyogenes) and methicillin-sensitive Staphylococcus aureus 2, 3
• Cephalexin 500 mg orally every 6 hours for 5 days provides excellent coverage against these organisms and is the preferred oral beta-lactam 1, 2
• Dicloxacillin 250–500 mg orally every 6 hours for 5 days is an equally effective alternative with comparable streptococcal and MSSA coverage 1, 2
• Amoxicillin 500 mg orally three times daily is another acceptable beta-lactam option 2

Treatment Duration

• Treat for exactly 5 days if clinical improvement occurs (reduced warmth, tenderness, improving erythema, absence of fever) 2, 4
• Extend treatment only if symptoms have not improved after the initial 5-day course; traditional 7–14 day regimens are unnecessary for uncomplicated cases 1, 2
• High-quality randomized controlled trial evidence demonstrates that 5-day courses are as effective as 10-day courses for uncomplicated cellulitis 2

When MRSA Coverage Is NOT Needed

• MRSA is an uncommon cause of typical cellulitis even in high-prevalence settings, so routine MRSA coverage is unnecessary 2, 3
• Do not add MRSA-active antibiotics unless specific risk factors are present 1, 2

When to Add MRSA Coverage

Add MRSA-active therapy only when any of these risk factors exist:

• Penetrating trauma to the surgical site 1, 2
• Purulent drainage or exudate visible at the wound 1, 2
• Known MRSA colonization or prior MRSA infection 2
• Systemic inflammatory response syndrome (fever >38°C, heart rate >90 bpm, respiratory rate >24 breaths/min) 1, 2
• Failure to respond to beta-lactam therapy after 48–72 hours 2

MRSA-Active Regimens (If Risk Factors Present)

• Clindamycin 300–450 mg orally every 6 hours for 5 days provides single-agent coverage for both streptococci and MRSA, but use only if local MRSA clindamycin resistance is <10% 2, 5
• Trimethoprim-sulfamethoxazole 1–2 double-strength tablets twice daily PLUS cephalexin 500 mg four times daily for dual coverage 2
• Doxycycline 100 mg orally twice daily PLUS a beta-lactam (cephalexin or amoxicillin) for combination therapy 2, 6
• Never use doxycycline or trimethoprim-sulfamethoxazole as monotherapy because they lack reliable activity against beta-hemolytic streptococci 2

Penicillin Allergy Management

• For non-immediate penicillin allergy, cephalexin remains acceptable because cross-reactivity is only 2–4% 2
• For true penicillin allergy, use clindamycin 300–450 mg orally every 6 hours (if local MRSA resistance <10%) 2, 5

Surgical Site Infection Considerations

• Surgical site infections (SSIs) rarely occur in the first 48 hours after surgery; fever during that period usually arises from non-infectious causes 1
• After 48 hours, SSI becomes more common, and careful wound inspection is indicated 1
• For SSIs with systemic signs (erythema >5 cm from wound edge, temperature >38.5°C, heart rate >110 bpm, WBC >12,000/µL), adjunctive systemic antibiotics are beneficial 1
• First-generation cephalosporin or antistaphylococcal penicillin is recommended for SSIs following clean operations on trunk/extremities 1
• Vancomycin, linezolid, daptomycin, or ceftaroline should be considered where MRSA risk factors are high (nasal colonization, prior MRSA infection, recent hospitalization, recent antibiotics) 1

Hospitalization Criteria

Admit patients with any of these findings:

• Systemic inflammatory response syndrome (fever, tachycardia, hypotension, altered mental status) 1, 2
• Signs of deep or necrotizing infection (severe pain out of proportion, skin anesthesia, rapid progression, "wooden-hard" tissue, gas or bullae) 2
• Severe immunocompromise or neutropenia 2
• Failure of outpatient therapy after 24–48 hours 2

Intravenous Therapy (If Hospitalization Required)

• Cefazolin 1–2 g IV every 8 hours is the preferred IV beta-lactam for uncomplicated cellulitis requiring hospitalization 1, 2
• Vancomycin 15–20 mg/kg IV every 8–12 hours for MRSA coverage if risk factors present 2
• Vancomycin PLUS piperacillin-tazobactam 3.375–4.5 g IV every 6 hours for severe cellulitis with systemic toxicity or suspected necrotizing infection 1, 2

Essential Adjunctive Measures

• Elevate the affected area above heart level for at least 30 minutes three times daily to promote gravity drainage of edema 2
• Examine interdigital toe spaces for tinea pedis, fissuring, or maceration if lower extremity involved, and treat if present 2
• Address predisposing conditions including venous insufficiency, lymphedema, chronic edema, obesity, and eczema 1, 2

Monitoring and Follow-Up

• Reassess within 24–48 hours to verify clinical response; treatment failure rates of approximately 21% have been reported with some oral regimens 2
• If no improvement after 48–72 hours, consider resistant organisms (MRSA), undrained abscess, deeper infection, or alternative diagnoses 2

Critical Pitfalls to Avoid

• Do not add MRSA coverage reflexively for typical cellulitis without specific risk factors; this overtreats 96% of cases and drives resistance 2, 3
• Do not automatically extend therapy to 7–10 days based on residual erythema alone; extend only if warmth, tenderness, or erythema have not improved 2
• Do not delay surgical consultation if any signs of necrotizing infection, deep abscess, or systemic toxicity develop 1, 2
• Do not use doxycycline or trimethoprim-sulfamethoxazole as monotherapy for typical cellulitis; they miss streptococcal pathogens in approximately 96% of cases 2