What is the treatment for cellulitis?

From the Guidelines

Cellulitis should be treated with antibiotics active against streptococci, with a recommended duration of 5 days, as this has been shown to be as effective as a 10-day course if clinical improvement has occurred by 5 days 1.

Treatment Approach

The treatment approach for cellulitis depends on the severity of the condition. For mild cases, oral antibiotics such as penicillin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, cephalexin, or clindamycin are suitable options 1.

• Key considerations include:
  • The choice of antibiotic should cover streptococci, as they are the most common cause of cellulitis.
  • In cases of uncomplicated cellulitis, a 5-day course of antimicrobial therapy is as effective as a 10-day course if clinical improvement has occurred by 5 days 1.
  • Elevation of the affected area and treatment of predisposing factors, such as edema or underlying cutaneous disorders, are recommended 1.

Severe Cases

More severe cases may require intravenous antibiotics such as ceftriaxone or vancomycin in a hospital setting 1.

• It is crucial to assess the severity of the condition and the patient's overall health to determine the best course of treatment.
• Hospitalization is recommended if there is concern for a deeper or necrotizing infection, for patients with poor adherence to therapy, for infection in a severely immunocompromised patient, or if the patient shows signs of systemic infection 1.

Additional Measures

While taking antibiotics, it is also important to:

• Elevate the affected area to promote gravity drainage of edema and inflammatory substances.
• Apply warm compresses to help reduce pain and inflammation.
• Take over-the-counter pain relievers like acetaminophen or ibuprofen as needed.
• Complete the full course of antibiotics even if symptoms improve to ensure the infection is fully cleared.

Monitoring and Follow-Up

It is essential to monitor the patient's condition and seek immediate medical attention if:

• Fever develops or increases.
• Pain increases.
• Red streaking from the infection site is observed.
• The affected area does not improve within 48 hours of starting antibiotics. Prompt treatment of cellulitis is crucial to prevent serious complications, such as the spread of the bacterial infection through skin and underlying tissues 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. Table 18 Cure Rates at the Test-of-Cure Visit for Microbiologically Evaluable Adult Patients with Complicated Skin and Skin Structure Infections Pathogen Cured ZYVOX n/N (%) Oxacillin/Dicloxacillin n/N (%) Staphylococcus aureus 73/83 (88) 72/84 (86) Methicillin-resistant S aureus 2/3 (67) 0/0 (-) Streptococcus agalactiae 6/6 (100) 3/6 (50) Streptococcus pyogenes 18/26 (69) 21/28 (75)

The recommended dosage for linezolid formulations for the treatment of complicated skin and skin structure infections is 600 mg IV or oral every 12 hours 2.

• Cellulitis treatment can be achieved with linezolid, with cure rates of 90% in clinically evaluable patients 2.
• The cure rates for Staphylococcus aureus and Methicillin-resistant S aureus were 88% and 67% respectively 2.
• Linezolid is effective against Gram-positive pathogens, including MRSA 2.
• The dosage for adult patients with infection due to MRSA is 600 mg q12h 2.

From the Research

Cellulitis Treatment Overview

• Cellulitis is a common condition, but there is uncertainty about the best approach to treatment, including the route of antibiotic administration and duration of therapy 3.
• A study published in 2020 found that the route of antibiotic administration (intravenous or oral) did not affect clinical outcome, and that patients with less severe cellulitis were more likely to improve with oral therapy alone 3.

Antibiotic Options

• A 2024 network meta-analysis of randomized controlled trials evaluated the efficacy and safety of various antibiotics for cellulitis and erysipelas, including azithromycin, cefaclor, and cephalexin 4.
• The study found no significant differences in cure rates among the antibiotics analyzed for cellulitis, but cefaclor demonstrated a favorable profile for curative outcomes 4.
• Ceftriaxone was identified as the least likely to induce diarrhea or vomiting, while pristinamycin showed promising results for erysipelas but carried a higher risk of rash 4.

Treatment Duration

• The 2020 study found no association between the duration of antibiotic therapy and clinical outcome, suggesting that a course length of more than 5 days may not provide additional benefit 3.
• The optimal duration of treatment for cellulitis remains uncertain, and further research is needed to determine the most effective approach 3, 4.