Is Keflex (Cephalexin) used for skin abscess?

From the Guidelines

Cephalexin (Keflex) is a suitable antibiotic option for the treatment of skin abscesses. The recommended dose is 250-500 mg orally every 6 hours for 5-7 days, or 500-1000 mg orally every 12 hours for 5-7 days, as suggested by 1.

Key Considerations

• In cases of more severe abscesses or those caused by methicillin-susceptible Staphylococcus aureus (MSSA), a longer duration of 7-10 days may be necessary, as indicated by 1.
• Incision and drainage of the abscess is often required in conjunction with antibiotic therapy for optimal treatment outcomes, as recommended by 1.
• It is essential to note that the choice of antibiotic should be guided by knowledge of the local patterns of susceptibility of S. aureus, especially local rates of MRSA, as suggested by 1.
• For patients who are allergic to penicillin, or if MRSA is a significant consideration, alternative antibiotics such as trimethoprim-sulfamethoxazole, doxycycline, or clindamycin may be used, as recommended by 1.

Important Points

• Cephalexin is effective against MSSA, but not against MRSA, as indicated by 1.
• The use of cephalexin should be guided by the results of culture and susceptibility testing, as suggested by 1.
• In cases of complex abscesses, such as perianal or perirectal abscesses, or abscesses in intravenous drug injection sites, empiric broad-spectrum antibiotic therapy with coverage of Gram-positive, Gram-negative, and anaerobic bacteria may be necessary, as recommended by 1.

From the FDA Drug Label

Skin and skin structure infections caused by Staphylococcus aureus and/or Streptococcus pyogenes

• Yes, Keflex (Cephalexin) is used for skin infections, which may include skin abscesses, caused by susceptible strains of Staphylococcus aureus and/or Streptococcus pyogenes 2

From the Research

Use of Keflex (Cephalexin) for Skin Abscess

• Keflex (Cephalexin) is used to treat skin abscesses, but its effectiveness has been studied in various contexts 3, 4, 5, 6, 7.
• A study from 2007 found that clinical cure rates were 90.5% in the placebo group and 84.1% in the cephalexin group, suggesting that antibiotics may be unnecessary after surgical drainage of uncomplicated skin and soft tissue abscesses caused by community strains of MRSA 3.
• Another study from 2006 compared the efficacy and safety of cefdinir to that of cephalexin in adolescents and adults with mild to moderate uncomplicated skin and skin structure infections, and found that both treatments had similar clinical cure rates 4.
• A study from 2004 found that incision and drainage without adjunctive antibiotic therapy was effective management of CA-MRSA skin and soft tissue abscesses with a diameter of <5 cm in immunocompetent children 5.
• A study from 2016 found that patients treated with I&D and antibiotics did no better than those treated with only I&D, regardless of the antibiotic activity, and that I&D was performed in only 60.6% of patients, and antibiotics were always prescribed 6.
• A study from 1991 compared the safety and efficacy of oral ofloxacin with that of cephalexin in microbiologic eradication of skin and skin-structure pathogens and the clinical treatment of skin and skin-structure infections, and found that both treatments were safe and effective 7.

Effectiveness of Cephalexin for Skin Abscess

• The effectiveness of cephalexin for skin abscess has been studied in various contexts, and the results suggest that it may not always be necessary to use antibiotics after surgical drainage of uncomplicated skin and soft tissue abscesses 3, 4, 5, 6.
• Cephalexin has been shown to be effective in eradicating causative pathogens and achieving clinical cure in patients with skin and skin-structure infections 4, 7.
• However, the use of cephalexin and other antibiotics for skin abscesses has also been associated with the development of antibiotic resistance, and therefore should be used judiciously 3, 6.

Comparison with Other Treatments

• Cephalexin has been compared to other treatments, such as cefdinir and ofloxacin, and has been found to have similar efficacy and safety profiles 4, 7.
• Incision and drainage (I&D) has been shown to be an effective treatment for skin abscesses, and may be used alone or in combination with antibiotics 3, 5, 6.