Endocrine- High ACTH- Normal Cortisol

[A2173]

I have been found to have high ACTH (37- 2007, 36- 3 weeks ago, 32- 1 week ago: all with normal range up to 24).  All other bloodwork (cortisol etc) is totally normal.  Nothing even border line.  Im lined up for MRI but my endo is at a loss.

My only other health issues are thyroid nodules (very small, thyroid tests normal) and alopecia areata (which has been VERY active during all three of these ACTH tests).   I also might tend towards low blood sugar (use Claritin D to pump it up), low BP (around 100/65).  I am 148lbs and 5'8" tall.  I have two kids- one is 18 months and still nursing.  Both kids took 1+ years to concieve and I have tested neg for ANA.

Anyway know why my ACTH could be high with nothing else?  My endo says next step is to go to a top endocrine center like university of virginia if I want to pursue it.  He doesnt know if its important to do that or not.