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Could it be Cow’s Milk Allergy? The Difference Between Lactose Intolerance and Cow’s Milk Allergy

Updated: Aug 25, 2022

It is estimated that 65% of the worldwide population suffers from lactose intolerance[1]. In contrast, Cow’s Milk Allergy (CMA) impacts an estimated 0.25% to 4.9% of the population and the prevalence is higher in children than in adults[2]. Although not as common as in children, allergies to cow’s milk in adults are often severe.[3]

The differences between lactose intolerance and milk allergy are often confused and misunderstood. Lactose intolerance is an impaired ability to digest the common sugar lactose1 that is found in milk and other dairy products. In contrast, Cow’s Milk Allergy (CMA) triggers an immune response in the body mediated by a specific class of immunoglobulins (type E or IgE) which can result in anaphylactic reactions. This not only can have long term implications on growth and nutrition for the individual but may be fatal in situations of severe anaphylaxis.2

Tabulated below are key areas of difference between CMA and Lactose Intolerance:

What are the symptoms of Lactose Intolerance?

Lactose is a disaccharide (“two sugars”) consisting of one molecule each of glucose and galactose. In normal digestion, an enzyme called lactase breaks down lactose in the small intestine and the resulting simple sugars are completely absorbed by that individual.

Lactose intolerant individuals do not make sufficient lactase to digest the lactose in their small intestine and this excess then passes to the colon. Bacteria that are present in the colon break down the excess lactose, producing hydrogen gas. Moreover, lactose in the colon may lead to severe water retention that produces discomforting gastrointestinal symptoms such as gas bloat, abdominal cramps, and in occasions, nausea and vomiting.[4]

The severity of symptoms can vary depending on the amount of lactose that an individual can tolerate, the amount of lactose ingested and the complexity of the consumed meal.

What are the symptoms of Cow’s Milk Allergy?

Cow’s Milk Allergy is the most common food allergy in infants and young children, and it can occur in formula-fed or breastfed infants. The symptoms and the severity of the reactions are wide-ranging and can include colic, skin reactions (such as red itchy rash, eczema or swelling of the lips, face and around the eyes), digestive problems (such as vomiting, abdominal pain or diarrhea) and hay fever-like symptoms (such as runny nose)[5].

The importance of testing and diagnosis of Cow’s Milk Allergy (CMA)

Cow’s Milk Allergy involves the immune system and can be severe, causing anaphylaxis and death. For this reason, it is very important to seek immediate professional help when symptoms appear. The clinician will carry out specific IgE allergy test to determine the immune response to CMA present in the person’s blood. Utilizing a blood test in an excellent alternative to traditional skin prick tests which only provide qualitative results, can be painful and usually result in uncomfortable secondary irritations.

If the results are positive for CMA, the clinician can then work with the patient to limit cow’s milk protein (dairy products) from the diet and subsequently monitor improvement in the patient’s symptoms.

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