For those of us who have tapered down to the single digits, the point at which our adrenal glands have to start functioning again, we can find ourselves quite uncertain as to whether we are having a flare or just suffering from "prednisone withdrawal" (which is actually adrenal insufficiency in my opinon). I received some helpful guidance from my Rheumy yesterday.
I have PMR/GCA diagnosed 4-1/2 years ago, and had 3 relapses over that time. I had reduced from 4.5 mg. prednisone to 4.25 mg. two weeks prior to my blood test yesterday for inflammatory markers. The first 2 days after reducing seemed fine and for the next 5 days I was very tired and had constant mild headache which gradually subsided by that 5th day. Then for the remaining week I was increasingly normal and more energetic.
My Rheumy said, "That is exactly what I would expect when reducing prednisone at that low level. If it had been active disease beginning to flare you would have just kept feeling increasingly worse." My blood inflammatory markers seemed to confirm this as they were low and exactly the same as the month before.
Each of us has to decide how bad we are feeling and when to call the doctor, but I found this to be a useful guideline. Basically (at low doses) if it hits you about 2 days after reducing and lasts about 5 days while slightly improving over those 5 days, then it seems more likely to be "pred withdrawal" than a flare. I appreciate having that guideline. I hope it helps some others in evaluating their own situation.