Petechiae are typically non-blanchable (i.e. it retains its color when pressed). You can discuss the workup with your personal physician, but it should include a CBC with an analysis of the peripheral smear. Bleeding tests like testing for the INR and PTT should be considered as well.
If there is question about the diagnosis after the initial workup, you can consider a bone marrow biopsy for a more comprehensive evaluation in conjunction with a hematology evaluation.
These options can be discussed with your personal physician.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b