What is the treatment for bullos impetigo?

Treatment of Bullous Impetigo

For limited bullous impetigo, use topical mupirocin 2% ointment applied three times daily for 5 days; for extensive disease or outbreaks, prescribe oral antibiotics for 7 days—dicloxacillin or cephalexin for methicillin-susceptible Staphylococcus aureus (MSSA), or clindamycin, doxycycline, or trimethoprim-sulfamethoxazole for suspected/confirmed MRSA. 1, 2

Understanding Bullous Impetigo

Bullous impetigo is caused exclusively by Staphylococcus aureus strains that produce exfoliative toxins, which cleave the dermal-epidermal junction to form fragile, thin-roofed vesicopustules that rupture easily, leaving crusted erythematous erosions surrounded by remnants of the blister roof. 1, 3 This represents approximately 30% of all impetigo cases and occurs more commonly in children under 5 years of age, particularly neonates. 4, 5

Diagnosis is typically clinical based on the characteristic appearance of large, flaccid bullae, often affecting intertriginous areas. 3 While Gram stain and culture can identify the causative organism and guide antibiotic selection, treatment without culture is reasonable in typical cases. 1

First-Line Treatment Approach

Limited Disease (Few Lesions)

Topical mupirocin 2% ointment applied three times daily for 5 days is the first-line therapy. 1, 2 The FDA-approved mupirocin ointment demonstrated 71% clinical efficacy in impetigo compared to 35% for placebo, with 94% pathogen eradication rates. 2 Alternatively, retapamulin applied twice daily for 5 days is equally effective. 1

Extensive Disease or Outbreaks

Oral antibiotics are recommended when patients have numerous lesions or during outbreaks affecting multiple people to decrease transmission. 1 A 7-day course with an agent active against S. aureus is the standard regimen. 1

Oral Antibiotic Selection Algorithm

For Methicillin-Susceptible S. aureus (MSSA):

• Dicloxacillin or cephalexin are the recommended first-line agents 1
• Oral penicillin V is seldom effective and should not be used 6

For Suspected or Confirmed MRSA:

• Doxycycline, clindamycin, or trimethoprim-sulfamethoxazole are recommended 1
• Important caveat: Approximately 50% of MRSA strains have inducible or constitutive resistance to clindamycin, with treatment failure rates reaching 21% in some series 1
• Trimethoprim-sulfamethoxazole covers MRSA but is inadequate for streptococcal infection if co-infection is suspected 3
• In areas with high MRSA prevalence, empirical MRSA coverage should be considered from the start 1

Monitoring and Treatment Failure

Monitor for clinical response within 24-48 hours when using oral antibiotics. 1 If progression occurs despite antibiotics, consider:

• Infection with resistant organisms 1
• Presence of a deeper, more serious infection than initially recognized 1
• Need for agents effective against MRSA such as vancomycin, linezolid, or daptomycin 1

For patients with severe infection or progression despite empirical therapy, base treatment on appropriate Gram stain, culture, and susceptibility results. 1

Special Considerations

Bacterial Identification and Resistance

It is important to swab the skin for bacteriological confirmation and antibiotic sensitivities, particularly in treatment failures or outbreaks. 4 Nasal swabs from the patient and immediate relatives should be performed to identify asymptomatic nasal carriers of S. aureus. 4

Systemic Therapy for Severe Cases

First-line systemic therapy for severe cases requiring intravenous treatment is flucloxacillin. 4 Vancomycin is an effective agent against MRSA for patients with severe or progressive infection. 1

Differential Diagnosis Warning

Critical pitfall: Do not confuse bullous impetigo with bullous pemphigoid, which is an autoimmune blistering disorder requiring entirely different treatment with topical or systemic corticosteroids and immunosuppressive agents. 1 Bullous pemphigoid typically affects elderly patients and has a chronic course requiring long-term immunosuppression. 7

Outbreak Management

In cases of outbreaks on wards and in nurseries, healthcare professionals should also be swabbed to identify carriers. 4 Oral antibiotics are specifically recommended for outbreaks affecting several people to decrease transmission. 1