After these blisters break open, the infected skin is very red, wet, and raw in appearance. This moisture begins forming a yellowish crust. It says an open wound such as an abrasion, insect bite, or minor injury can turn into impetigo. The germ that causes impetigo is Streptococcal. This bacteria of often present in sand and soil.
Dirty fingers can infect broken skin through casual contact and itching.
It continues by saying the crusts that form should be removed by soaking the area with warm water. After the crusts are removed, continue by scrubbing the sores with warm, soapy water. The same book says Bacitracin ointment may help stop impetigo from spreading to other people. Although it is rare, impetigo epidemics are often responsible for an ailment of the kidneys called glomerulonephritis. Symptoms of this illness are high blood pressure, dark brown urine, and a headache.