The diagnosis of impetigo is generally straightforward and can be done easily by a doctor through examining the affected area. Information about the recent scrapes, cuts or insect bites on the affected area is also confirmed by the doctor. During diagnosis the general practitioner also tries to find out whether impetigo has occurred on top of the other skin conditions like scabies. Besides examining the affected skin other tests may also be done in condition when symptoms of the infection are very severe and has spread to various parts of the body.

Moreover when infection keeps recurring or does not respond to treatment then also other tests may be prescribed by the doctor. The diagnosis of impetigo can also be done by gently wiping the crusted area with a swab so as to see that which germ is the cause of the infection. The swab also helps in determining the presence of other infection like shingles and ringworms and it also helps in deciding the type of antibiotic to be used. When a person suffers from recurring infection the swab may also be taken from the nose in order to determine whether that the bacteria are present there. Thus medical judgments and culture tests are done to diagnose impetigo infection.