Lactose intolerance is a physiological response to poorly digested and/or absorbed lactose in the gut due to lactase deficiency or inactivity and does not involve the immune system.6 Cows’ milk protein allergy is an adverse immune system reaction to cows’ milk protein that can be either immunoglobulin E (IgE) or non-IgE mediated.6

Lactose intolerance and cows’ milk protein allergy are often incorrectly used interchangeably due to similarities in the gastrointestinal clinical symptoms.3 Misdiagnosis or delayed diagnosis may result in inappropriate treatment options and/or unnecessary dietary restriction.3