 [ Symptoms ] possible tdap allergic reaction hives  i had a tdap shot last saturday and have had hives off an on all week could this be an allergic reaction even though it was not sudden [ Disease ] maybe i do not know anything about your medical history but hearing your pulse in your ear could be a condition called pulsatile tinnitus you can look this up consider seeing a good ent specialist for a proper examination while pt can have common innocent causes there are a few more serious causes that may need to be ruled out again based on a thorough medical history this is not an easy issue to medically investigate so make sure to find an ent that has expertise in this area