Sounds to me she is more reflux. I was told its hard to diagnose babies with mspi and its a hit and miss thing. If she was LI, more symptoms include excess gass, bloatedness, foamy pooh's/diahrrea, some have eczema. She might not be allergic to dairy, but she might be hypersensitive to it. Babies digestive systems are weak and some struggle to break down lactose in dairy. My dd is not diagnosed with it, but she too has silent reflux and does the arching of her back, screaming and fussiness. During nites she moves around constantly and thruses her head left and right and has lots of gas. She is using lf formula now, and I put colief in the b.milk that i express. It seems to have lessened her gas quite a bit, which makes me wonder if the comfort she was on wasnt causing the gas (as its said to give excess gas, but should be able to release easily)She is less fussy now too and doesnt cry after every feed anymore. I am still on the fence if I am going to try nutramigen and see if it settles her once and for all! But dont want to spend money for nothing.
My ds had projectile vomiting and reflux, and gass too, but as a first time mom I had no idea what is causing it. If I had known, I wouldve definitely tried different formula on him! I am actually quite dissapointed in our medical system as no one even suggested this or seemed to know what could've caused it!