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, and elevation of the affected area to promote gravity drainage of edema and inflammatory substances 1.

Treatment Approach

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

• Oral antibiotics like cephalexin (500 mg four times daily), dicloxacillin (500 mg four times daily), or amoxicillin-clavulanate (875/125 mg twice daily) for 5 days are usually effective for mild cases.
• More severe cases may require intravenous antibiotics such as ceftriaxone (1-2 g daily) or vancomycin (15-20 mg/kg every 8-12 hours) in a hospital setting.

Management

While taking antibiotics, it is essential to:

• Elevate the affected area to reduce swelling and improve circulation.
• Apply warm compresses to help reduce pain and inflammation.
• Take over-the-counter pain relievers like acetaminophen or ibuprofen as needed.

Monitoring and Follow-up

It is crucial to complete the full course of antibiotics even if symptoms improve. Patients should seek immediate medical attention if they develop:

• Fever over 100.4°F
• Increasing pain
• Redness spreading rapidly
• Red streaks extending from the infected area, as these may indicate worsening infection 1. Antibiotics work by killing the bacteria causing the infection, typically Streptococcus or Staphylococcus species, while elevation and warm compresses help reduce swelling and improve circulation to speed healing.

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 for 10 to 14 days 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 Streptococcus agalactiae and Streptococcus pyogenes, with cure rates of 100% and 69% respectively 2.

From the Research

Cellulitis Treatment Overview

• Cellulitis is a common skin infection that can be challenging to distinguish from other conditions due to the lack of a gold standard diagnostic test 3.
• The selection of antibiotics for cellulitis treatment is determined by patient history, risk factors, severity of clinical presentation, and the most likely microbial culprit 3.

Antibiotic Route and Duration

• There is uncertainty about the benefit of intravenous (IV) over oral (PO) antibiotic therapy, and the appropriate duration of treatment for cellulitis 4.
• A study found that patients with cellulitis who received only PO therapy were more likely to improve at day 5 compared to those who received at least a single dose of IV therapy, and were as likely to return to normal activities at day 10 and day 30 4.
• The same study found no association between the duration of antibiotic therapy and outcome as measured at day 10 and day 30, suggesting that a course length of > 5 days may not result in additional benefit 4.

Antibiotic Options

• A network meta-analysis of randomized controlled trials evaluated the efficacy and safety of first- and second-line antibiotics for cellulitis and erysipelas, including azithromycin, cefaclor, cephalexin, and others 5.
• The analysis found no significant differences in cure rates for cellulitis among the antibiotics analyzed, with cefaclor demonstrating the most favorable profile for curative outcomes 5.
• Ceftriaxone was identified as the least likely to induce diarrhea or vomiting, while pristinamycin showed the most promising results in achieving cure rates for erysipelas, but with a higher risk of rash 5.