A number of well-designed comparison studies have shown the superiority of oral or
injectable antibiotics over typical treatment in the treatment of
impetigo contagiosa.
Erythromycin,
phenoxymethyl penicillin, intramuscular
benzathine penicillin G as well as
clindamycin,
cefaclor and
amoxicillin with
clavulanic acid have been shown to be extremely effective. Because of significant differences in study design, it is difficult to compare drugs investigated in different studies. Intramuscular
benzathine penicillin G consistently has been associated with the highest cure rates, especially in studies specifically of streptococcal
impetigo. It is unclear whether these high cure rates reflect superior efficacy or are the result of lesser compliance with oral medication, but the latter explanation is quite likely. This information generally translates into daily practice as a recommendation of a
penicillin or an
erythromycin preparation for streptococcal
impetigo unless the lesions are small and few in number, in which case topical
therapy is probably sufficient. If oral
antibiotics are prescribed they should be given for 10 days. Systemic as opposed to topical
antibiotics should be considered more strongly in situations where the incidence of
impetigo is high, since these drugs are clearly superior in sterilizing the lesions quickly to prevent transmission. Other situations that favor the use of systemic as opposed to topical
antibiotics include the presence of nephritogenic strains in the population, whether endemic or epidemic, more severe or spreading lesions and a population with poor hygiene.