When Should a Child with Cow's Milk Allergy be Given a Soya-Based Infant Formula?

A prospective randomised study 1 included 170 infants of the average age of 7 months (2 - 11 months) with milk allergy, confirmed with a double-blind, placebo-controlled challenge. Half of the infants (n = 80) were assigned to receive a soya formula (Soija-Tutteli by Valio). If it was suspected that the formula was not tolerated, a double-blind, placebo-controlled challenge was performed. Ten per cent of the children developed allergic symptoms. Moreover, the suitability of the soya formula remained uncertain in 18 % of the cases (delayed, mild symptoms). A repeated double-blind, placebo-controlled challenge would have been needed to ascertain the matter. Soya was not tolerated in 5 of 20 cases in the age group less than 6 months, whereas of the infants aged 6 - 12 months only 3 of 60 reacted to soya (p = 0.01). However, the under 6 month cohort was small; only 20 infants. Of the children receiving soya-based formula, 58 % were confirmed to have IgE antibodies to cow's milk. Adverse reactions to soya were similar in IgE-associated and non-IgE-associated cow's milk allergy (p = 0.25). The study cohort did not include patients with enterocolitis or other enteropathy.

A randomised, multicentre study evaluated the tolerability of soya-based infant formula (Isomil, Abbott) in children with IgE-associated cow's milk allergy (n = 93, age 3 months - 3.5 years, 3.2 % less than 6 months, 17.2 % 6 months - 1 year) 2. The diagnosis of milk allergy was based either on a double-blind, placebo-controlled food challenge or repeated previous history of an anaphylactic reaction to milk. The criteria included the emergence of cow's milk induced immediate (within 4 hours) cutaneous, respiratory or gastrointestinal symptoms. Soya allergy was confirmed with a randomised, double-blind, placebo-controlled food challenge in 14 % of the cohort. The proportion of infants less than 6 months of age was small (3.2 %). A negative skin prick test correlates well with the suitability of soya, as compared with food challenge testing.

References

• Klemola T, Vanto T, Juntunen-Backman K, Kalimo K, Korpela R, Varjonen E. Allergy to soy formula and to extensively hydrolyzed whey formula in infants with cow's milk allergy: a prospective, randomized study with a follow-up to the age of 2 years. J Pediatr 2002 Feb;140(2):219-24. [PubMed]
• Zeiger RS, Sampson HA, Bock SA, Burks AW Jr, Harden K, Noone S, Martin D, Leung S, Wilson G. Soy allergy in infants and children with IgE-associated cow's milk allergy. J Pediatr 1999 May;134(5):614-22. [PubMed]