Steroids - duration of benefits?

[h202]

We are likely going to start a 4 week steroid taper next week for my son's PANDAS.  Following two months of antibiotics with some improvements, the primary symptoms we still have are major anxiety, increased hyperactivity, and very significant stereotypies (specifically: intense imagery movements).  

We previously did a 5 day steroid burst, and saw good effects on day 5, that lasted for 3 days.  I understand this suggests that a full steroid taper is likely to be helpful.  

I see a lot of people on this site say how steroids were fantastic, but that they rarely have lasting effects.

Question for everyone:  Did the steroids-benefits go away because your child was ultimately exposed to another trigger?  Or was it because the benefits simply faded over time?  

[bigmighty]

My son ended up with a very long-term remission after a three week steroid taper (that was following two months on antibiotics).  My son remained on antibiotics for an additional full year during/after the taper so the benefits lasted.  It was sort of amazing.  About two months AFTER he finished the steroid taper, the light switch simply turned back off.  Went from full-blown OCD/anxiety to zero of either.