Is cefdinir (Cefdinir) effective for treating bullous impetigo?

Cefdinir for Bullous Impetigo Treatment

Cefdinir is effective for treating bullous impetigo, particularly when oral therapy is indicated for extensive lesions, but it is not considered first-line therapy when methicillin-resistant Staphylococcus aureus (MRSA) is suspected. 1, 2

Bullous Impetigo: Causative Organisms and Presentation

• Bullous impetigo is caused exclusively by Staphylococcus aureus strains that produce toxins cleaving the dermal-epidermal junction 1
• It presents as fragile, thin-roofed vesicopustules that may rupture, creating crusted, erythematous erosions 1
• Unlike non-bullous impetigo, which can be caused by both S. aureus and Streptococcus pyogenes, bullous impetigo is solely staphylococcal in origin 1, 3

Treatment Options for Bullous Impetigo

Topical Treatment

• For limited lesions, topical antibiotics like mupirocin or retapamulin twice daily for 5 days are first-line therapy 1
• Topical therapy is as effective as oral antibiotics for limited impetigo 1, 3

Oral Antibiotic Therapy (When Indicated)

• Oral therapy is recommended for patients with numerous lesions or in outbreaks affecting several people 1
• For bullous impetigo, oral therapy should be active against S. aureus 1
• Since S. aureus isolates from impetigo are usually methicillin-susceptible, dicloxacillin or cephalexin are recommended first-line options 1
• When MRSA is suspected or confirmed, doxycycline, clindamycin, or sulfamethoxazole-trimethoprim (SMX-TMP) are recommended 1

Cefdinir's Role in Treating Bullous Impetigo

• Cefdinir is FDA-approved for uncomplicated skin and skin structure infections caused by Staphylococcus aureus (including β-lactamase producing strains) and Streptococcus pyogenes 2
• As an extended-spectrum semisynthetic cephalosporin, cefdinir has activity against S. aureus comparable to second-generation agents 1
• Cefdinir is stable to hydrolysis by commonly occurring plasmid-mediated beta-lactamases 4
• Clinical studies have demonstrated cefdinir's efficacy in treating uncomplicated skin infections with clinical cure rates comparable to cephalexin 5

Treatment Algorithm for Bullous Impetigo

1. For limited lesions:

   • Use topical mupirocin or retapamulin twice daily for 5 days 1

2. For extensive lesions requiring oral therapy:

   • First-line (MSSA likely): Dicloxacillin or cephalexin for 7 days 1
   • Alternative when first-line not suitable: Cefdinir 300mg twice daily for 10 days 2, 5
   • When MRSA is suspected: Doxycycline, clindamycin, or SMX-TMP 1

Important Considerations and Caveats

• Penicillin alone is not effective for bullous impetigo since it's caused by S. aureus 1, 3
• Cefdinir is ineffective against methicillin-resistant S. aureus (MRSA) 2
• Cefdinir has a convenient dosing schedule (once or twice daily) compared to some alternatives like cephalexin (four times daily) 5
• In areas with high MRSA prevalence, empiric therapy should cover MRSA until culture results are available 1
• Systemic antimicrobials should be used during outbreaks of poststreptococcal glomerulonephritis to eliminate nephritogenic strains 1
• Cefdinir is generally well tolerated with diarrhea being the most common adverse event 4, 6

Special Populations

• Dosage adjustment is required for patients with markedly compromised renal function (creatinine clearance <30 mL/min) 2
• Elderly patients do not require dosage adjustment unless they have markedly compromised renal function 2
• For pediatric patients, cefdinir is administered at 14 mg/kg/day in one or two daily doses 6