COMMENTARY · September 26, 2014
TAKE-HOME MESSAGE
This review discusses cow’s milk allergy and covers the diagnostic approach, strict avoidance as the only therapeutic option, and primary preventive measures.
Cow’s milk allergy is the most common food allergy in children, and understanding the many aspects of the condition is important for primary and secondary healthcare providers.
Expert Comment by David Rakel MD, FAAFP
ABSTRACT
This review summarizes current evidence and recommendations regarding cow’s milk allergy (CMA), the most common food allergy in young children, for the primary and secondary care providers. The diagnostic approach includes performing a medical history, physical examination, diagnostic elimination diets, skin prick tests, specific IgE measurements, and oral food challenges. Strict avoidance of the offending allergen is the only therapeutic option. Oral immunotherapy is being studied, but it is not yet recommended for routine clinical practice. For primary prevention of allergy, exclusive breastfeeding for at least 4 months and up to 6 months is desirable. Infants with a documented hereditary risk of allergy (i.e., an affected parent and/or sibling) who cannot be breastfed exclusively should receive a formula with confirmed reduced allergenicity, i.e., a partially or extensively hydrolyzed formula, as a means of preventing allergic reactions, primarily atopic dermatitis. Avoidance or delayed introduction of solid foods beyond 4–6 months for allergy prevention is not recommended.
CONCLUSION
For all of those involved in taking care of children’s health, it is important to understand the multifaceted aspects of CMA, such as its epidemiology, presentation, diagnosis, and dietary management, as well as its primary prevention.
European Journal of Pediatrics
Cow’s Milk Allergy: Evidence-Based Diagnosis and Management for the Practitioner
Eur. J. Pediatr. 2014 Sep 26;[EPub Ahead of Print], C Lifschitz, H Szajewska
Cow’s milk protein (CMP) allergy is the most common food allergy in infants, affecting 2% to 3%. This goes down to 0.5% if a child is breastfed. There are two main types: IgE-mediated and non–IgE mediated (see chart below for a clinical comparison).
The main CMPs that the immune system reacts to are casein and whey. Casein is the protein that is found in curdled milk; it is in high concentrations in cheese. (Remember it this way: casein curdles to make cheese.) Whey is the protein that is left over after milk curdles. It is the main protein in milk serum and is a byproduct of cheese production that cheese manufacturers sell as a protein source.
How does it present?
If urticaria or angioedema develop within hours of introducing CMP into a child’s diet, an IgE-mediated CMP allergy is likely. If eczema or GI symptoms (diarrhea, gas, bloating, blood in stool) develop hours to days later, a non–IgE CMP allergy is likely.
*Please note that an allergy is defined as “a hypersensitivity reaction triggered by specific immunologic mechanisms.” Some would call a non-IgE reaction an intolerance or sensitivity. But, according to this definition, one could also call it an allergy.
How is it diagnosed?
The gold standard is to eliminate CMP and see if symptoms resolve. If they do, then rechallenge to see if symptoms recur. If urticaria and/or angioedema are present, consider skin-prick testing for an IgE-mediated reaction, which may last longer than non–IgE CMP allergy.
How is it prevented?
Encourage at least 4 months of breastfeeding; 6 months is better. Delaying introduction of CMP into the diet does not reduce the risk.
How is it treated?
What is the best way to reintroduce milk?
Most kids will outgrow CMP allergy after 1 year of age. Start with small amounts of baked or heated milk products. Heating the milk helps break down the CMP, making it more tolerable.