Congenital lactose intolerance is very rare and is an inherited metabolic disorder rather than an allergy.先天性的乳糖不耐受是非常罕见的遗传性的代谢紊乱，而并非过敏。
Some premature babies have a temporary form of lactose intolerance because their bodies are not yet producing lactase.一些早产的宝宝会暂时的有乳糖不耐受症状是因为他们体内还未开始分泌乳糖分解酶。