From the Guidelines
The best treatment for cellulitis of the lower extremities is empiric antibiotic therapy targeting Streptococcus and Staphylococcus species, the most common causative organisms, as recommended by the Infectious Diseases Society of America in their 2014 guidelines 1. For mild to moderate uncomplicated cellulitis, oral antibiotics such as cephalexin (500 mg four times daily), dicloxacillin (500 mg four times daily), or clindamycin (300-450 mg three times daily) for 5-10 days are typically effective, 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. Some key points to consider in the treatment of cellulitis include:
- Elevation of the affected area and treatment of predisposing factors, such as edema or underlying cutaneous disorders, are recommended 1.
- In lower extremity cellulitis, clinicians should carefully examine the interdigital toe spaces because treating fissuring, scaling, or maceration may eradicate colonization with pathogens and reduce the incidence of recurrent infection 1.
- Outpatient therapy is recommended for patients who do not have SIRS, altered mental status, or hemodynamic instability 1.
- For more severe infections or those with systemic symptoms, intravenous antibiotics may be necessary, such as cefazolin (1-2 g every 8 hours) or vancomycin (15-20 mg/kg every 12 hours) if MRSA is suspected 1. In addition to antibiotics, elevation of the affected limb, proper wound care if applicable, and pain management are important supportive measures. Patients should also be advised to monitor for spreading redness, increasing pain, fever, or streaking, which may indicate worsening infection requiring medical reassessment. The effectiveness of antibiotic therapy stems from its ability to eliminate the bacterial infection while the body's immune system works to reduce inflammation and repair damaged tissue. Adequate hydration and rest also support recovery.
From the Research
Treatment Options for Cellulitis of the Lower Extremities
The treatment of cellulitis of the lower extremities typically involves the use of antibiotics, with the goal of covering the most likely causative organisms, such as Streptococcus and Staphylococcus aureus 2. The choice of antibiotic may depend on various factors, including the severity of the infection, the presence of risk factors for methicillin-resistant S. aureus (MRSA), and the patient's medical history.
Antibiotic Regimens
- Narrow-spectrum antibiotics, such as cephalexin, may be effective for uncomplicated cellulitis, while broad-spectrum antibiotics may be reserved for more severe cases or those with risk factors for MRSA 3.
- Macrolides and streptogramins have been shown to be more effective than penicillin antibiotics in some studies 4.
- Trimethoprim-sulfamethoxazole and clindamycin may be preferred empiric therapies for outpatients with cellulitis in areas with a high prevalence of community-associated MRSA infections 5.
Duration and Route of Antibiotic Treatment
- The duration of antibiotic treatment is typically 5 days, but may be extended if symptoms do not improve 2.
- Oral antibiotics may be as effective as intravenous antibiotics for uncomplicated cellulitis, and may be preferred due to their convenience and lower cost 4, 6.
Factors Affecting Treatment Outcome
- The presence of risk factors for MRSA, such as prior MRSA exposure or intravenous drug use, may affect the choice of antibiotic regimen 2.
- The severity of the infection, as well as underlying medical conditions, such as immunosuppression or chronic kidney disease, may also impact treatment outcome 2, 5.