I am a thyroid patient with a history of thyroditis and irregular menses. i have been having this low grade fever for years now. comes and goes. i have had all tests done but nothing comes out.i got my cbc and thyroid checked today.my esr is 80 which usually stays elevated.hb is 11.7.tlc is 9000 platelets 250000. and thyroid is normal. ehat could be the cause of the fever. can thyroditis be relapsed because i have heard that it is self limiting amd usually doesn t come back.