What is the treatment for cellulitis?

From the Guidelines

Cellulitis treatment should typically involve a 5- to 6-day course of antibiotics active against streptococci, as recommended by the American College of Physicians 1. The goal of treatment is to reduce morbidity, mortality, and improve quality of life by effectively managing the infection.

Key Considerations

• For mild cases, oral antibiotics like cephalexin, dicloxacillin, or clindamycin are usually effective 1.
• More severe cases may require intravenous antibiotics such as ceftriaxone, vancomycin, or piperacillin-tazobactam in a hospital setting 1.
• Treatment should be adjusted if MRSA is suspected, with options including trimethoprim-sulfamethoxazole or doxycycline 1.

Additional Recommendations

• Patients should elevate the affected area to reduce swelling, take over-the-counter pain relievers like acetaminophen or ibuprofen as needed, and keep the area clean and dry 1.
• Warm compresses may help improve circulation and healing 1.
• Patients should complete the full course of antibiotics even if symptoms improve, and seek immediate medical attention if fever increases, the redness spreads rapidly, or they develop streaking from the infection site 1.

Rationale

The 2021 guidelines from the American College of Physicians recommend a 5- to 6-day course of antibiotics for nonpurulent cellulitis, which is consistent with the goal of reducing morbidity, mortality, and improving quality of life 1. The choice of antibiotic should be based on the severity of the infection, the presence of systemic signs of infection, and the suspected causative pathogens 1. By following these recommendations, clinicians can provide effective treatment for cellulitis and improve patient outcomes.

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. The cure rates for complicated skin and skin structure infections were 90% in linezolid-treated patients.

• Staphylococcus aureus: 88%
• Methicillin-resistant S aureus: 67%
• Streptococcus agalactiae: 100%
• Streptococcus pyogenes: 69% The recommended dosage for linezolid formulations for the treatment of complicated skin and skin structure infections is 600 mg IV or oral q12h for 10 to 14 days 2.

From the Research

Treatment of Cellulitis

• The treatment of cellulitis should initially cover Streptococcus and methicillin-sensitive S. aureus, with expansion for methicillin-resistant S. aureus (MRSA) in cases of cellulitis associated with specific risk factors 3.
• Five days of treatment is sufficient with extension if symptoms are not improved 3.
• Addressing predisposing factors can minimize the risk of recurrence 3.
• The diagnosis of cellulitis is based primarily on history and physical examination 3, 4.
• Treatment of uncomplicated cellulitis should be directed against Streptococcus and methicillin-sensitive S. aureus 3, 4.
• Failure to improve with appropriate first-line antibiotics should prompt consideration for resistant organisms, secondary conditions that mimic cellulitis, or underlying complicating conditions such as immunosuppression, chronic liver disease, or chronic kidney disease 3.

Antibiotic Treatment

• The use of cephalexin plus trimethoprim-sulfamethoxazole compared to cephalexin alone did not result in higher rates of clinical resolution of cellulitis in the per-protocol analysis 5.
• However, because imprecision around the findings in the modified intention-to-treat analysis included a clinically important difference favoring cephalexin plus trimethoprim-sulfamethoxazole, further research may be needed 5.
• No evidence was found to support the superiority of any one antibiotic over another, and antibiotics with activity against methicillin-resistant Staphylococcus aureus did not add an advantage 6.
• Use of intravenous antibiotics over oral antibiotics and treatment duration of longer than 5 days were not supported by evidence 6, 7.

Route and Duration of Antibiotic Therapy

• There is no evidence of difference in clinical response rates for antibiotic route or duration 7.
• The evidence base for antibiotic treatment decisions in cellulitis is flawed by biased comparisons, short follow-up, and lack of data around harms of antibiotic overuse 7.
• Future research should focus on developing patient-tailored antibiotic prescribing for cellulitis to reduce unnecessary antibiotic use 7.