Sometimes another bacterium, Staphylococcus aureus, can also be isolated from impetigo lesions. Impetigo begins as a cluster of small blisters that expand and rupture within the first 24 hours. The thin yellow fluid that drains from the ruptured blisters quickly dries forming a honey-colored crust. Impetigo develops most frequently on the legs, but may also be found on the arms, face and trunk. There is usually no fever.
Impetigo occurs more commonly during the summer and early fall.
Impetigo may be treated with an antibiotic taken by mouth or by application of an antibiotic ointment to the affected areas. A person with impetigo is probably no longer infectious after 24 hours of adequate antibiotic treatment. Without treatment, a person may be infectious for several weeks. Rarely, GABS may invade beyond the skin of a person with impetigo and cause more serious illnesses. Persons with impetigo may also develop post-streptococcal glomerulonephritis or scarlet fever.