Cow’s milk allergy (CMA) is the most common food allergy in infants and young children – about 2 % to 5 % of all children suffer from this condition. It is an overreaction of the immune system to one or more proteins contained in cow’s milk. Cow’s milk protein is usually one of the first complementary foods to be introduced into the infant’s diet and is commonly consumed throughout childhood as part of a balanced diet. Very rarely, exclusively breast-fed babies can react to cow’s milk proteins.
These proteins can be passed on through their mother’s milk if she has been consuming dairy products. In this situation, clinical guidelines recommend that breast-feeding is continued due to its benefits and the mother tries to eliminate cow’s milk protein from her diet. CMA generally affects children of under the age of 2 to 3 years.
The symptoms caused by CMA are varied and may affect several organ systems, e.g. the skin, the digestive or the respiratory tract, possibly resulting in skin rash, eczema, vomiting, diarrhoea, colic, wheezing or excessive crying. The allergic reactions can set in very rapidly (e.g. severe breathing problems, vomiting), but they can also be delayed or require a larger portion of food (e.g. a glass of milk) to set them off. An example of a delayed reaction would be a skin rash or diarrhoea which can take up to 3-5 days to appear.
In formula-fed infants and older children avoiding whole cow’s milk proteins will be necessary to eliminate the symptoms of CMA. This requires adequate dietary substitutes to be determined with the advice of a health care professional. As already mentioned, in case you breastfeed your child it will be recommended that you change your diet by eliminating all milk proteins.
If that doesn't help, your child's doctor will advise to consider a substitute, ranging from formulas containing proteins which have been broken down, to formulas that contain no cow's milk protein at all, so-called amino acid-based formulas.
DRAMCA. WAO Journal April 2010
Wood. PEDIATRICS Vol. 111 No. 6 June 2003