Introduction
Cow´s milk protein allergy (CMPA) is the most common cause of food
allergy in young children.[1] The estimated prevalence of cow’s milk
allergies ranges around 2% to 3% in the first year of life and around
60% of those are IgE-mediated reactions [2, 3]. Most children will
outgrow this allergy after the first years of childhood, but is
estimated that 15% of them will carry this sensitivities into the
2nd decade of life and 35% of these children will
have allergic reactions to other foods [3]. Children with a systemic
reaction to cow’s milk should be given a hypoallergenic formula, such as
an EHF or AAF. By definition, they must be tolerated by 90% of children
with CMPA with a 95% CI. [4] These hypoallergenic formulas are
either partially hydrolyzed, extensively hydrolyzed (short peptides
below 1500 Da) or given as an amino acid based formula.
The pathophysiologic mechanism of CMPA include IgE mediated, mixed
IgE-Non IgE and non IgE mediated reactions. IgE mediated Milk reactions
are known to be the 3rd most common cause of food
induced anaphylaxis [5]. The related mortality from anaphylaxis in
children is around 1% and accounts for 0.2 % of all pediatric
intensive care admissions in the USA [5]. IgE reactions are
characterized by acute onset usually minutes to hours after the exposure
of an allergen with various presentations. Common symptoms include
skin/mucosal (urticarial rash, angioedema, flushing), respiratory
symptoms (i.e, wheezing, shortness of breath, stridor), abdominal
symptoms (i.e, nausea, vomiting, abdominal pain) and cardiovascular
instability (i.e. low blood pressure, tachycardia)[6].
In children with a severe IgE mediated reaction to cow’s milk they may
be given an EHF. In rare cases where they develop an allergic reaction
to an EHF, an AA formula is then given. Although, the intolerance rates
of EHF in CMA children can be approximately 10%, an immediate systemic
reaction is very rare. [7]