I would really increase her med’s to be honest.   A short period on doube or triple dose may be what it needs to help her with the virus.  Although anti-biotics do not help, raised cortisol levels are needed to fend off a virus.  It is a normal immune system response as far as we knew.  I would do that if the temop is up and down.  What may be occuring is when she has her med’s she is fine and then a few hours later her temp is up when the steroids are low in her bloods.  It IS possible for that to happen I feel and it did with Ashley.  In this day and age when kids are getting different doses at different times of day--during illness those doses should be very much similar.  The difference between being in "normal" mode and "double" mode is that when they are ill we are supposed to double or triple the daily dose as a whole and then divide that by three or four to arrive at the correct dose.  So they get more even doses acros that area where they are ill and it keeps the cortisol levels constant and UP where they need to be during illness.  On normal  dosing it is perhaps 5mg here and 10mg there or 2.50mg wherever.  So if a child is sick there are areas in the day where the cortisol levels would be much much higher to help their boides cope and of course if you give something small like 2.50mg it is not a large enough dose to handle the illness.  Even if it IS in the afternoon when their cortisol levels are low, during illness the whole thing chances.  

Perhaps you should double or triple for a day or two and see how she copes.