Ava's CD story as posted on celiac.com
Your son's symptoms sound just like my daughter, Ava. At a year old she finally started fitting into 6-12 month clothes and then when she turned 2 she started wearing 12-18 month clothes. At 2 1/2 she'd moved up to 18 month size finally. She was always very happy and has tons of energy and was an awesome sleeper. She just never grew, and had a distended belly, never a solid poop, but it was never exactly diarrhea either. We figured she was small just because she didn't ever eat much and that that too was the cause of her distended belly. She also has a rash on her bum that we were told was eczema but it doesn't react like regular eczema, the only thing that ever helped it was neosporin at every single diaper change, and all that did was stop it from blistering and weeping. When she started talking at 2 we noticed that everytime she'd refuse to eat something she'd say "No eat. Tummy sad." Always the same thing. She was basically living off bananas and raisins.
Fall of 2011, I was describing on our family blog all her weird habits or abnormalities (the rash, liquid poo, etc.) and someone commented that those things all sounded just like her son who has Celiac disease and maybe I should look into it. And so I did. I read up on it and when I took our baby (not Ava) in for her 6 month check up, I mentioned to the doctor that COULD it be celiac disease, and our (awesomely open) pediatrician's face lit up like I had the answer and though it wasn't Ava's appointment, she immediately sent us to the lab to have Ava's blood tested. Before she let us go though she warned us that due to Ava's age the tests may be inaccurately negative.
Well, indeed, her blood test showed negative, and the pediatrician recommended I get an appointment with a GI specialist.
I didn't. I just can't handly putting someone so tiny through that. Instead, I put her on a gluten-free diet. At the end of the first month being gluten free(January 2012) she started finally fitting 2T clothes. We are now 3 months in to her being gluten-free. Or almost gluten-free, I still have some work to do on getting better at reading labels or not being lazy. One day I just let her have macaroni and cheese with her big sister and not only did she end up with liquid poo almost immediately, but she developed a rash all over her body as well. Anyway. Three months almost clean and her belly is no longer distended. Her rash is almost completely gone. We no longer hear "tummy sad". She's started gaining weight and finally has gotten up to 23 pounds! She is still anemic though, so we've got to work on that. I feel fully confident in my own diagnosis that she has Celiac disease and I can't imagine putting her back on gluten so they can do the official tests to diagnose her.
So yes, some Celiac babies are calm and excellent sleepers. Though now that she's off gluten, she doesn't sleep as well, so perhaps she slept in defense to get away from the pain?
(this was my input today at http://www.celiac.com/gluten-free/topic/91216-celiac-or-overly-concerned-mommy/)