D.M.
B.,
My son is two as well, and his lactose intolerance does not present itself as spitting up, but severe stomach upset, cramping and loose stool. He was diagnosed when he was still in the NICU after birth (8 weeks early), and other than breastmilk, his Doctor recommended Soy Milk or other Milk substitutes. We tried, Almond but possible nut issues have steered us back to Soy.
There is a huge difference between being allergic to dairy and lactose intolerance. It's not fun, but I've seen the rash and the pain some kids experience with severe allergies.
From my family experience, it almost sounds like acid reflux. My cousin's little boy has had reflux since he was born, and is now on a special diet so they can void meds if at all possible.
I would make an appt. with your son's Doctor. Keep a journal of when it happens, and how long the episodes last and take that with you.
Good luck!