My 18 month old grandaughter has been having marks on her body for about a month. Is there any way to determine if they are flea bites? Her other grandmother did have fleas in her house at one time, but says she no longer has them. I know they are extremely difficult to get rid of in a home. I wonder if they are still there, although no one else has bites. Could you describe what the bites actually look like and the progression of a bite? How long would a bite mark last? Her marks are on her arms, face,legs, back, behind her neck, and in her hair. the doctor's office has just said not to bring her in, that all kids go through rashes!!