From the Guidelines
Cellulitis should be treated with an antimicrobial agent active against streptococci, and the recommended duration of antimicrobial therapy is 5 days, but treatment should be extended if the infection has not improved within this time period. The treatment approach depends on the severity of the infection and the presence of systemic signs of infection. For typical cases of cellulitis without systemic signs of infection, an antimicrobial agent active against streptococci is recommended 1.
Treatment Approach
- For mild cases, oral antibiotics are typically effective, and the choice of antibiotic should be based on the suspected causative organism and local resistance patterns.
- For cellulitis with systemic signs of infection, systemic antibiotics are indicated, and coverage against methicillin-susceptible S. aureus (MSSA) may be considered 1.
- For patients with severe infection, broad-spectrum antimicrobial coverage may be considered, and vancomycin plus either piperacillin-tazobactam or imipenem/meropenem is recommended as a reasonable empiric regimen 1.
Additional Measures
- Elevation of the affected area and treatment of predisposing factors, such as edema or underlying cutaneous disorders, are recommended 1.
- In lower extremity cellulitis, clinicians should carefully examine the interdigital toe spaces because treating fissuring, scaling, or maceration may eradicate colonization with pathogens and reduce the incidence of recurrent infection 1.
- Outpatient therapy is recommended for patients who do not have systemic inflammatory response syndrome (SIRS), altered mental status, or hemodynamic instability, while hospitalization is recommended for patients with severe infection or those who are severely immunocompromised 1.
From the FDA Drug Label
The cure rates in clinically evaluable patients with complicated skin and skin structure infections were 90% in linezolid-treated patients and 85% in oxacillin-treated patients The cure rates by pathogen for microbiologically evaluable patients are presented in Table 18. The treatment for cellulitis, which is a type of skin and skin structure infection, is linezolid (ZYVOX), with a recommended dosage of 600 mg IV or oral every 12 hours for 10 to 14 days.
- Key points:
- Linezolid is effective against MRSA and other Gram-positive pathogens.
- The cure rate for linezolid-treated patients with complicated skin and skin structure infections was 90%.
- The recommended treatment duration is 10 to 14 days. 2
From the Research
Treatment Overview
- The treatment of cellulitis should initially cover Streptococcus and methicillin-sensitive S. aureus, with expansion for methicillin-resistant S. aureus (MRSA) in cases of cellulitis associated with specific risk factors 3.
- Five days of treatment is sufficient with extension if symptoms are not improved 3, 4.
- Addressing predisposing factors can minimize the risk of recurrence 3.
Antibiotic Treatment
- Trimethoprim-sulfamethoxazole, cephalexin, or clindamycin can be used as empiric outpatient therapy for cellulitis 5.
- Trimethoprim-sulfamethoxazole has a higher treatment success rate compared to cephalexin 5.
- Clindamycin success rates are higher than those of cephalexin in patients with culture-confirmed MRSA infections, moderately severe cellulitis, and obesity 5.
- Weight-based dosing of clindamycin and trimethoprim/sulfamethoxazole is associated with better outcomes in cellulitis 6.
Duration of Treatment
- A short-course (5 days) of therapy has equal efficacy to a standard (10 days) course of therapy for patients with uncomplicated cellulitis 4.
- Extension of treatment beyond 5 days may be necessary if symptoms are not improved 3, 4.
Considerations
- The diagnosis of cellulitis is based primarily on history and physical examination 3.
- Failure to improve with appropriate first-line antibiotics should prompt consideration for resistant organisms, secondary conditions that mimic cellulitis, or underlying complicating conditions such as immunosuppression, chronic liver disease, or chronic kidney disease 3.