Lactose intolerance is a common gastrointestinal condition caused by the inability to digest and absorb dietary lactose. Primary lactose intolerance is the most common type of lactose intolerance. It is one of the most common forms of food intolerance and occurs when lactase activity is reduced in the brush border of the small bowel mucosa. People may be lactose intolerant to varying degrees, depending on the severity of these symptoms. When lactose is not digested, it is fermented by gut microbiota, leading to abdominal pain, bloating, flatulence, and diarrhea with a considerable intraindividual and interindividual variability in the severity of clinical manifestations. These gastrointestinal symptoms are similar to cow's milk allergy and could be wrongly labeled as symptoms of "milk allergy." There are important differences between lactose intolerance and cow's milk allergy. Therefore, a better knowledge of these differences could limit misunderstandings in the diagnostic approach and in the management of these conditions. [Pediatr Ann. 2021;50(4):e178-e185.].

中文翻译：

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儿科患者的乳糖不耐症和对牛奶过敏的常见误解。

乳糖不耐症是一种常见的胃肠道疾病，由无法消化和吸收膳食乳糖引起。原发性乳糖不耐症是最常见的乳糖不耐症类型。它是最常见的食物不耐受形式之一，当小肠粘膜刷状缘的乳糖酶活性降低时就会发生。根据这些症状的严重程度，人们可能会有不同程度的乳糖不耐受。当乳糖不被消化时，它会被肠道微生物群发酵，导致腹痛、腹胀、肠胃气胀和腹泻，临床表现的严重程度在个体内部和个体之间存在相当大的差异。这些胃肠道症状类似于牛奶过敏，可能会被错误地标记为“牛奶过敏”的症状。乳糖不耐症和牛奶过敏之间有重要区别。因此，更好地了解这些差异可以减少对诊断方法和这些疾病管理的误解。[小儿安。2021;50(4):e178-e185.]。