Sara:  My daughter is on the tiny side also, now 3 1/2yrs old and 25lbs. She is on the 5% mark on the charts.  I do worry about her size, our endo says it is not related to meds.... I have read on the florinef insert that one of the side effects can be suppression of growth in children when florinef is used in conjunction with cortisone or a similiar glucocordicoid. She is on a low dose and pedipred is kept as low as possible also. I have recently switched her florinef dose to giving it in the morning instead of at night just to see if it makes a difference.We do not have a choice as these meds are life sustaining so I figure if she is tiny because of the meds this is better than the alternative. I joke that she is "Tiny But Tough" We get a lot of mileage out of her clothes, still in size 2 and her feet have finlly grown to a 6, she was shoesize 5 for 2 years! The important thing is that she is mainly healthy, learning and developing on par with others her age and a joy to have!!! I hope that you get answers to your concerns.  Thanks for sharing your information with us.