From the Guidelines
The first-line treatment for lower leg cellulitis is a 5- to 6-day course of antibiotics active against streptococci. According to the most recent guidelines, patients with nonpurulent cellulitis should receive a short course of antibiotics, particularly for those able to self-monitor and who have close follow-up with primary care 1. The recommended antibiotic course is 5-6 days, which is supported by recent studies and guidelines 1.
Key Considerations
- The antibiotic choice should target the most common causative organisms, which are typically Streptococcus species and Staphylococcus aureus.
- Patients with penicillin allergy can be treated with alternative antibiotics such as clindamycin.
- In addition to antibiotics, patients should elevate the affected limb to reduce swelling, take analgesics for pain relief, and mark the border of the erythema to monitor progression or improvement.
- Adequate hydration and rest are also important for recovery.
Special Cases
- Patients with signs of systemic illness, significant comorbidities, or lack of improvement within 48-72 hours of oral therapy may require hospitalization for intravenous antibiotics.
- Patients with penetrating trauma, evidence of MRSA infection elsewhere, nasal colonization with MRSA, injection drug use, or systemic inflammatory response syndrome may require additional antimicrobial coverage against MRSA and streptococci 1.
- Patients should be advised to seek immediate medical attention if the redness spreads rapidly, they develop high fever, or the pain becomes severe.
Duration of Treatment
- The recommended duration of antimicrobial therapy is 5 days, but treatment should be extended if the infection has not improved within this time period 1.
- A 5- to 6-day course of antibiotics is recommended for nonpurulent cellulitis, as supported by recent guidelines and studies 1.
From the Research
First-Line Treatment for Lower Leg Cellulitis
The first-line treatment for lower leg cellulitis typically involves the use of antibiotics that cover Streptococcus and methicillin-sensitive Staphylococcus aureus (S. aureus) 2. The choice of antibiotic may be adjusted based on the presence of specific risk factors for methicillin-resistant S. aureus (MRSA), such as a history of MRSA exposure or certain social and occupational factors.
Antibiotic Options
Some studies suggest the following antibiotic options for the treatment of uncomplicated cellulitis:
- Cephalexin, which is effective against Streptococcus and methicillin-sensitive S. aureus 2, 3
- Trimethoprim-sulfamethoxazole, which has activity against community-associated MRSA and may be preferred in areas with high MRSA prevalence 4
- Clindamycin, which is also effective against MRSA and may be used in patients with severe cellulitis or those who are obese 4
Treatment Duration
The typical duration of treatment for cellulitis is 5 days, with extension of treatment if symptoms are not improved 2. It is essential to address predisposing factors to minimize the risk of recurrence.
Key Points
- The diagnosis of cellulitis is based primarily on history and physical examination 2
- Treatment of uncomplicated cellulitis should be directed against Streptococcus and methicillin-sensitive S. aureus 2
- Failure to improve with appropriate first-line antibiotics should prompt consideration for resistant organisms, secondary conditions that mimic cellulitis, or underlying complicating conditions 2
- Penicillin may be effective in preventing recurrent cellulitis in patients with a history of multiple episodes 5