A common, contagious skin infection caused by Streptococci. Streptococcal impetigo is a common infection of young children and occurs on the legs, arms and face. The infection usually causes blisters first, followed by yellow, crusty scabs. The infected areas should be cleaned with soap and water. Impetigo should also be treated with antibiotics. Without antibiotic treatment, impetigo can lead to more serious infections and, occasionally, to severe kidney problems. Impetigo is contagious until after the second day of antibiotic treatment.