What is the recommended treatment for cellulitis?

From the Guidelines

The recommended treatment for cellulitis is oral antibiotics targeting common causative bacteria, primarily Streptococcus and Staphylococcus species, with a recommended duration of antimicrobial therapy of 5 days, but treatment should be extended if the infection has not improved within this time period 1.

Key Considerations

• Typical cases of cellulitis without systemic signs of infection should receive an antimicrobial agent that is active against streptococci, such as penicillin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, cephalexin, or clindamycin 1.
• For patients with penicillin allergies, clindamycin 300-450 mg four times daily or trimethoprim-sulfamethoxazole (TMP-SMX) are appropriate alternatives 1.
• If MRSA is suspected, doxycycline 100 mg twice daily or TMP-SMX DS twice daily should be considered 1.
• Patients should elevate the affected limb to reduce swelling, take acetaminophen or ibuprofen for pain relief, and mark the border of the infection with a pen to monitor progression.
• Severe cases with systemic symptoms (fever, rapid heart rate), extensive involvement, or in immunocompromised patients require intravenous antibiotics and possibly hospitalization 1.

Special Cases

• For patients whose cellulitis is associated with penetrating trauma, evidence of MRSA infection elsewhere, nasal colonization with MRSA, injection drug use, or SIRS, vancomycin or another antimicrobial effective against both MRSA and streptococci is recommended 1.
• In severely compromised patients, broad-spectrum antimicrobial coverage may be considered, with vancomycin plus either piperacillin-tazobactam or imipenem-meropenem as a reasonable empiric regimen for severe infections 1.

Monitoring and Follow-up

• Patients should seek immediate medical attention if the infection worsens despite treatment, red streaks develop, or fever develops.
• The affected area should be regularly monitored for signs of improvement or worsening, with adjustments to treatment made as necessary.

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 recommended treatment for cellulitis, which is a type of skin and skin structure infection, is linezolid 600 mg IV or oral every 12 hours for 10 to 14 days 2.

• Key points:
  • Linezolid is effective against MRSA and other Gram-positive pathogens.
  • The cure rates for linezolid-treated patients with complicated skin and skin structure infections were 90%.
  • The treatment duration is determined by the site and severity of the infection, and the patient's clinical response.

From the Research

Treatment of Cellulitis

The recommended treatment for cellulitis typically involves the use of antibiotics. The choice of antibiotic depends on the severity of the infection and the suspected causative organism.

• For uncomplicated cellulitis, antibiotics such as penicillin, amoxicillin, and cephalexin are often used, as they are effective against β-hemolytic streptococci and methicillin-sensitive Staphylococcus aureus 3.
• In areas with a high prevalence of community-associated methicillin-resistant Staphylococcus aureus (MRSA), antibiotics with activity against MRSA, such as trimethoprim-sulfamethoxazole and clindamycin, may be preferred 4.
• However, studies have shown that the addition of trimethoprim-sulfamethoxazole to cephalexin does not improve outcomes for patients with uncomplicated cellulitis 5, 6.
• A cost-effectiveness analysis found that cephalexin is the most cost-effective option for outpatient empiric therapy of cellulitis, unless the probability of MRSA infection is high, in which case clindamycin may be more cost-effective 7.

Antibiotic Options

Some common antibiotic options for the treatment of cellulitis include:

• Cephalexin: a first-generation cephalosporin effective against β-hemolytic streptococci and methicillin-sensitive Staphylococcus aureus 5, 6.
• Trimethoprim-sulfamethoxazole: a combination antibiotic with activity against MRSA, which may be preferred in areas with a high prevalence of MRSA 4, 7.
• Clindamycin: a lincosamide antibiotic with activity against MRSA, which may be used as an alternative to trimethoprim-sulfamethoxazole 4, 7.
• Penicillin and amoxicillin: effective against β-hemolytic streptococci and methicillin-sensitive Staphylococcus aureus, but may not be effective against MRSA 3.