How do you know if your infant has lactose intolerance?

My 19 month old has for most of her life been not fond of milk. She had colic in the first 3 months of her life. And as she gets older its getting harder to get her to drink milk. She refuses to take it while she’s awake and when she is asleep she’ll only drink 3 – 4 ounces. We do occasionally hear gurgling in her stomach while feeding her milk, but we’re not sure if that is just normal sound of liquid in the stomach or if its an allergic reaction.