From the Guidelines
For the treatment of cellulitis, a 5- to 6-day course of antibiotics active against streptococci is recommended, particularly for patients able to self-monitor and who have close follow-up with primary care. This approach is supported by the most recent guidelines, including those from the American College of Physicians 1. The choice of antibiotic should be based on the severity of the infection, patient factors such as allergies and kidney function, and local resistance patterns.
- For mild to moderate uncomplicated cellulitis, oral antibiotics such as cephalexin, dicloxacillin, clindamycin, or amoxicillin-clavulanate are effective options.
- If MRSA is suspected, trimethoprim-sulfamethoxazole (TMP-SMX) or doxycycline should be considered.
- For severe infections requiring hospitalization, intravenous antibiotics such as vancomycin, ceftriaxone, or piperacillin-tazobactam may be necessary. It's also important to note that the 2014 IDSA guideline recommends extending treatment if the infection has not improved after 5 days 1, and the 2019 National Institute for Health and Care Excellence (NICE) guideline recommends a course of 5 to 7 days 1. However, the most recent and highest quality study suggests that a 5- to 6-day course is sufficient for most patients 1. Key considerations in the management of cellulitis include:
- Elevation of the affected area
- Rest
- Monitoring for improvement within 48-72 hours
- Seeking immediate medical attention if the infection worsens, spreads, or if systemic symptoms develop.
From the Research
Effective Antibiotic Medications for Cellulitis
- Levofloxacin has been shown to be effective in treating uncomplicated cellulitis, with a 5-day course being as effective as a 10-day course 2.
- Trimethoprim-sulfamethoxazole and clindamycin are preferred empiric therapies for outpatients with cellulitis in areas with a high prevalence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections 3.
- Oral beta-lactam therapy (OBLT) using oral flucloxacillin plus probenecid has been found to be tolerable and have similar outcomes to outpatient parenteral antimicrobial therapy (OPAT) 4.
- High-dose cephalexin (1000 mg) has been shown to have fewer treatment failures compared to standard-dose cephalexin (500 mg) in a pilot randomized controlled trial 5.
Dosage and Duration of Antibiotic Therapy
- A 5-day course of levofloxacin (500 mg/d) has been found to be as effective as a 10-day course in treating uncomplicated cellulitis 2.
- The duration of antibiotic therapy does not appear to be associated with outcome, with no additional benefit seen with courses longer than 5 days 6.
- High-dose cephalexin (1000 mg) four times daily for 7 days has been shown to be effective in treating cellulitis, but with a higher proportion of minor adverse events 5.
Route of Antibiotic Administration
- Oral antibiotic therapy has been found to be as effective as intravenous (IV) therapy in treating cellulitis, with no association between the route of administration and clinical outcome 6.
- IV antibiotic therapy may be preferred in patients with more severe cellulitis or those who have received antibiotics prior to trial entry 6.