Cow's Milk Protein Allergy

Cow's milk allergy refers to an immunological reaction to milk protein. It is one of the commonest food protein allergies with an estimated prevalence of 0.5% to 3% at 1 y of life. The disease may be IgE or non-IgE mediated or mixed with a wide range of symptoms often involving multiple organ systems. Gastrointestinal manifestations are common in non-IgE disease and may consist of enteropathy, proctocolitis, colic, reflux-like symptoms, constipation, enterocolitis syndrome and eosinophilic esophagitis. The gold standard for diagnosis remains a double-blind placebo-controlled oral challenge. Specific IgE and skin prick tests may predict severe and persistent disease, and aid in deciding on reintroduction or oral immunotherapy; however, they do not contribute to a definitive diagnosis as they indicate only sensitization. In practice, an elimination diet followed by open challenge under medical supervision is often used for diagnosis except when symptoms are severe such as anaphylaxis. Management consists of the elimination of the allergen with resolution of symptoms between 1-4 wk later depending on the type of allergy. Extensively hydrolyzed and Amino acid formulas are used to substitute milk in infants. Soy-based formulas are often utilized in resource-limited settings. Tolerance to the protein develops over time and periodic reintroduction should be attempted every six months after the initial one year of elimination diet. Oral immunotherapy is a newer treatment technique for IgE-mediated disease. There is no firm evidence on prevention apart from recommending breast feeding in early life along with initiating complementary feeding between 4-6 mo age.