To the Editor: Australian consensus guidelines for selecting formulas for infants with cows milk protein allergy (CMPA) have recently been published.1 We reviewed formula choices and outcomes for 51 children with immediate allergic reactions to cows milk protein who were referred to one of us (S S M) in a tertiary specialist clinic over a 2-year period before the guidelines were published. The formula was selected by the referring specialist medical practitioner in 44 cases (and by S S M in the other seven).

Of the 51 children (mean age at initial reaction to cows milk protein, 7.8 months), 42 had skin and/or gastrointestinal features, and nine had an anaphylactic reaction with respiratory and/or cardiac features. Forty-six children had a positive skin prick test to cows milk protein, and one had a positive radioallergosorbent test. Four children with immediate (< 30 min) reactions of generalised erythema and/or angioedema (3) or vomiting (1), but a negative skin prick test, were also included.

Soy was the most common formula used, followed by extensively hydrolysed formula (EHF) (Box). Three of eight children commenced on EHF had allergic reactions, with urticaria and angioedema, and one child also had a transient (60 s) cough. Three children were given partially hydrolysed formula (PHF), with one experiencing an immediate cutaneous reaction.

These observations suggest that, in clinical practice, soy is frequently a satisfactory first choice for children with CMPA, as suggested in the guidelines.1 Some children with CMPA will also react to EHF, providing a rationale for choosing amino acid-based formula as a first-line treatment prior to allergy evaluation in children with anaphylaxis to cows milk protein. As about 5% of infants with CMPA also react to EHF,2 some allergists advocate the introduction of EHF under medical supervision in either all children with immediate CMPA3 or only those who have had severe life-threatening reactions.4

Although PHF is tolerated by a significant proportion of children (70%) with immediate CMPA,3 it is not recommended for the treatment of CMPA1 due to its high content of potentially allergenic cows milk protein. The fact that three children with CMPA were given PHF suggests there is confusion in the prescribing community, and that the availability of the new guidelines may help in achieving a more appropriate choice of formula.