The prevalence of cow’s milk protein allergy (CMPA) varies from 2% to 7.5% in early childhood. Cow’s milk is usually one of the first complementary feeds to be introduced into the diet and most infant formula milks are based on cow’s milk protein. In addition, cow’s milk can be transmitted via breast milk if the breastfeeding mother is eating dairy.
Cow’s milk protein allergy can cause immediate type (IgE mediated) or delayed type (non IgE mediated) allergic reactions. IgE-mediated cow’s milk induced allergic reactions typically occur within minutes of exposure and range in severity from mild (skin symptoms such as hives and swellings) to severe anaphylaxis. Non IgE mediated delayed type cow’s milk allergy can present with gut disorders such as severe colic or reflux, persistent diarrhea, or blood in the stools, usually in the infant or young child.
The long term prognosis in both types of cow’s milk allergy is good. The delayed type allergy is typically outgrown by 2-3 years of age, but may be more persistent in some severe cases. In the immediate IgE mediated type, at least half of children tolerate cow’s milk by 8 years and 80% by 16 years.
Tolerance is initially acquired to extensively heated cow’s milk e.g. baked foods.
Around 80% of children with CMPA tolerate extensively heated cow’s milk, such as butter baked into biscuits or cupcakes. Your allergist should ask specifically about baked milk products, and investigate your child further if you are not sure.
The cornerstone of treatment for cow’s milk allergic children is the avoidance of all cow’s milk protein, including cow’s milk derived infant formulas and other dairy products. The only exception may be extensively heated cow’s milk protein (CMP), such as in baked products, which can be continued in those tolerant to them. Parents should read food labels and recognize terms that may indicate the presence of cow’s milk protein. These include terms such as whey, lactose, casein, caseinate, lactalbumin and lactoglobulin.
In formula -fed infants, an appropriate hypoallergenic infant formula will need to be selected and must be advised by your allergist. Some children, especially those with an immediate type cow’s milk allergy, will tolerate soya-based milks; these children will be carefully selected by your allergist. Potential advantages of soya-based milks are the good taste and affordability. Goat’s milk formulas and the so-called “HA” or “partially hydrolysed” formulas are NOT suitable for cow’s milk allergy sufferers.
If a breastfed child is symptomatic, and found to be allergic to cow’s milk protein, then the lactating mother will be advised and guided on elimination of cow’s milk and dairy from her own diet.