My dogs have fleas. can flea bites cause petechia? friend has it on neck and i have it on legs.

Yes: Some flea born illnesses will present with petechiae. You should see the doctor to see if they are petechiae. That can be a dangerous sign.

Flea bites: Flea bites cause lesions resembling insect bites not petechiae. Not sure who diagnosed your skin lesions as petechiae! these are bleeding spots under the skin, and a re not caused by flea bites and if indeed that is the case you need to have them checked asap.