The lesions are generally asymptomatic. The skin around the nose and mouth and the limbs are the sites most commonly affected. The palms and soles are not affected. A beta-hemolytic streptococci, but skin injury by insect bites, abrasions, lacerations, and burns allows the streptococci to invade. A beta-hemolytic streptococci may sometimes be isolated from early lesions, but most lesions Acute nephritis Acute nephritis tends to occur when many individuals in a family have impetigo.
Most cases occur in the southern part of the United States.
Infants under 1 years of age are rarely affected by nephritis following impetigo. The nares are the most common sites of carriage, but the perineum, axillae, and toe webs may also be colonized. Because some cases of impetigo have a mixed infection of staphylococci and streptococci, penicillin is inadequate for treatment. Mupirocin ointment is the first topical antibiotic approved for the treatment of impetigo.