Does a petechiae rash always warrant a trip to the doctor or can it be watched before going? on thigh

Petechiae: You can get petechiae from a wide variety of processes- from chronic irritation of your skin to infectious diseases that can be serious to blood or bone marrow disorders. Unless you are clear on the cause you may wish to involve your doctor especially if you have easy brusing or gum bleeding or blood in urine or stool. If you can feel the petechiae (raised) it may be a vasculitis.