Treatment of Cellulitis in Adult Patients

Antibiotic Selection

The American College of Physicians recommends a 5-day course of antibiotics active against streptococci and Staphylococcus aureus as the first-line therapy for uncomplicated cellulitis in adults, with extension if the infection has not improved within this time period 1, 2
For typical cases without systemic signs of infection, antimicrobial agents active against streptococci, such as penicillin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, cephalexin, or clindamycin are recommended 1
When MRSA is a concern, consider trimethoprim-sulfamethoxazole, clindamycin, or linezolid 3, 2
For diabetic patients with mild to moderate infections, broader coverage including both streptococci and S. aureus is recommended with options such as amoxicillin-clavulanate, trimethoprim-sulfamethoxazole, or clindamycin 2

For patients with systemic signs of infection, intravenous antibiotics are recommended 3, 4
Initial empiric therapy should include vancomycin, linezolid, daptomycin, telavancin, or ceftaroline when MRSA risk factors are present 3
For severe cellulitis with skin sloughing or concern for necrotizing infection, broader coverage with vancomycin plus piperacillin-tazobactam or a carbapenem is recommended 4

The recommended initial duration is 5 days, with extension if the infection has not improved within this time period 1, 2
For severe infections with skin sloughing, longer courses (10-14 days) may be necessary based on clinical response 4
Evaluation of response should occur every 2-5 days initially for outpatients 2

Elevation of the affected area to promote drainage of edema and inflammatory substances is recommended 1, 4
Identification and treatment of predisposing factors such as edema, obesity, eczema, venous insufficiency, and toe web abnormalities is recommended 3, 2
Systemic corticosteroids could be considered in non-diabetic adult patients to reduce inflammation 3, 1

Severe infections with SIRS (systemic inflammatory response syndrome) require hospitalization 1, 4
Altered mental status or hemodynamic instability require hospitalization 4
Concern for deeper or necrotizing infection requires hospitalization 1, 4

For patients with 3-4 episodes of cellulitis per year despite treatment of predisposing factors, prophylactic antibiotics should be considered 3, 1
Options include oral penicillin or erythromycin twice daily for 4-52 weeks, or intramuscular benzathine penicillin every 2-4 weeks 3, 2
This prophylactic program should continue as long as predisposing factors persist 3

For surgical site infections, suture removal plus incision and drainage should be performed 3
Blood cultures should be obtained in patients with severe systemic features, malignancy, or unusual predisposing factors 4