Impetigo

Impetigo is an infection of the skin classically caused by staph aureus.
The primary lesion is a thin walled vesicle that breaks easily. There is lateral extension of the superficial lesion with, typically, a honey colored crust at the edge.
Satellite lesions can appear, and spread to remote areas of the skin is common.
Although initially caused by streptococci, by one week most lesions are also growing staphylococci, which may become the predominant organism.
Streptococcal impetigo is a major cause of post-streptococcal acute glomerular nephritis (AGN).
The probability of developing AGN rests with the type of streptococcus infecting the lesion, with M type 49 being a relatively common cause of AGN.

Treatment:

• Topical mupirocin or fusidic* acid are very effective for the streptococcal lesion, with or without staphylococcal overgrowth.
• If there is any reason to suspect a nephritogenic strain of streptococcus, systemic antibiotic therapy, with penicillin, is indicated.
• Fluoxacillin, cloxacillin, erythromycin

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