What are the appropriate antibiotics for the treatment of cellulitis?

From the Guidelines

Cellulitis should be treated with a 5- to 6-day course of antibiotics active against streptococci, particularly for patients able to self-monitor and who have close follow-up with primary care. For mild to moderate uncomplicated cellulitis, oral antibiotics are usually sufficient. First-line treatment options include cephalexin (500 mg four times daily), dicloxacillin (500 mg four times daily), or clindamycin (300-450 mg three times daily) 1. If MRSA is suspected, appropriate options include trimethoprim-sulfamethoxazole (1-2 double-strength tablets twice daily), doxycycline (100 mg twice daily), or clindamycin. The choice of antibiotic should be guided by the severity of the infection, the presence of comorbidities, and the likelihood of MRSA infection.

Some key points to consider when treating cellulitis include:

• The importance of completing the full course of antibiotics, even if symptoms improve before finishing treatment 1
• The need to elevate the affected area to reduce swelling, keep the area clean and dry, and take over-the-counter pain relievers as needed 1
• The potential for severe or extensive disease, signs and symptoms of systemic illness, or associated comorbidities to require more aggressive treatment, such as intravenous antibiotics 1
• The role of incision and drainage in the treatment of abscesses, and the potential need for antibiotic therapy in addition to drainage 1

It's also important to note that the optimal duration of antibiotic therapy for cellulitis is not well established, and further study is needed to evaluate the effectiveness of different treatment durations 1. However, based on current evidence, a 5- to 6-day course of antibiotics is recommended for most patients with uncomplicated cellulitis 1.

From the FDA Drug Label

Complicated Skin and Skin Structure Infections Adult patients with clinically documented complicated skin and skin structure infections were enrolled in a randomized, multi-center, double-blind, double-dummy trial comparing study medications administered IV followed by medications given orally for a total of 10 to 21 days of treatment. The cure rates in clinically evaluable patients were 90% in linezolid-treated patients and 85% in oxacillin-treated patients A separate study provided additional experience with the use of ZYVOX in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. The cure rates in microbiologically evaluable patients with MRSA skin and skin structure infection were 26/33 (79%) for linezolid-treated patients and 24/33 (73%) for vancomycin-treated patients

The antibiotic linezolid is effective in treating cellulitis caused by Gram-positive bacteria, including MRSA.

• The cure rates for linezolid-treated patients were 90% in one study and 79% in another study for MRSA infections.
• Linezolid can be used as an alternative to vancomycin or oxacillin for the treatment of complicated skin and skin structure infections, including cellulitis. 2

From the Research

Cellulitis Antibiotics Treatment

• The treatment of cellulitis typically involves the use of antibiotics, with the choice of antibiotic depending on the severity of the infection and the patient's medical history 3, 4, 5, 6, 7.
• A study published in 2019 found that a combination therapeutic regimen of amoxicillin + clavulanic acid was the most commonly used treatment option and was linked with the shortest duration of stay in the hospital 3.
• Another study published in 2020 found that there was no association between the route of antibiotic administration (intravenous or oral) and clinical outcome, and that the duration of antibiotic therapy did not affect the outcome as measured at day 10 and day 30 4.
• A systematic review and meta-analysis published in 2019 found that there was no evidence to support the superiority of any one antibiotic over another, and that antibiotics with activity against methicillin-resistant Staphylococcus aureus did not add an advantage 5.
• A review published in 2021 noted that antibiotic selection is determined by patient history and risk factors, severity of clinical presentation, and the most likely microbial culprit 6.
• A network meta-analysis published in 2024 found that there were no significant differences in cure rates among antibiotics for cellulitis, but that ceftriaxone had the fewest gastrointestinal side effects, and that pristinamycin showed the highest cure rates for erysipelas but with a higher risk of rash 7.

Antibiotic Options

• Amoxicillin + clavulanic acid: linked with the shortest duration of stay in the hospital 3.
• Cefaclor: demonstrated the most favorable profile for curative outcomes in cellulitis 7.
• Ceftriaxone: had the fewest gastrointestinal side effects 7.
• Pristinamycin: showed the highest cure rates for erysipelas but with a higher risk of rash 7.
• Azithromycin, cephalexin, cloxacillin, erythromycin, flucloxacillin, clindamycin, penicillin, roxithromycin: were also assessed in the network meta-analysis, but did not demonstrate significant differences in cure rates 7.

Treatment Duration

• A study published in 2020 found that the duration of antibiotic therapy did not affect the outcome as measured at day 10 and day 30 4.
• A systematic review and meta-analysis published in 2019 found that treatment duration of longer than 5 days was not supported by evidence 5.