One of our PANDAS kids has this issue (the most severe, DS14), the other does not. DS14 is about 80 lbs, 4'11". He also has delayed puberty. Endo doc says they can give testosterone shots to start puberty, but we are hesitant b/c not sure what it might do to his PANDAS/PANS symptoms. His appetite is low, but he will eat, as long as we remind him to, but very picky eater. I, his dad, am not large or tall, and our family doc says not to worry. His sister who also has PANDAS, is now 17...and even on ADD meds with a low appetite is normal height and weight, 5'5", 130 lbs. we are hoping once puberty kicks in, he will grow, but it is a worry. Dr Latimer thinks he has some OCD eating issues. He doesn't want his food to touch, but otherwise has never complained about it not being right. He can put down a happy meal with the best of em...it just might take an hour. Thyroid tests, celiac, etc have always been negative. So, I don't know what the problem is...just another mystery with him.