Escalation of soya cross-allergy in infants with cow's milk allergy

Cow's milk allergy (CMA) is a common condition in infants, requiring alternative protein sources in their diets. Soya milk has become a popular substitute, especially in developing countries where it is a more affordable option compared to expensive hypoallergenic feeds for infants with insufficient breast milk supply. However, recent observations have shown an increase in soya cross-allergic reactions among infants with CMA.

To determine how often infants diagnosed with CMA also had soya cross-allergy and to examine the symptoms and outcomes of these infants at 2 years of age.

Data from two pediatric centers were analyzed, looking at clinical records of children under 2 years old diagnosed with CMA from August 2015 to July 2023, divided into two four-year periods.

The records of 432 infants with CMA were analyzed. In the first four-year period from August 2015 to July 2019, 142 infants were studied, with 27 (19%) found to have soya-protein allergy as well. In the second four-year period, a total of 290 infants were studied, and soya allergy was found in 136 babies (47%). This represents a significant increase (P < 0.0001) in cases of soya protein cross-allergy among infants with CMA. The most common symptoms observed were gastroesophageal reflux disorder (39%), followed by failure to thrive, bloody diarrhea, watery diarrhea, and constipation. At 2 years of age, these infants showed significant growth failure compared to infants with CMA only.

In conclusion, this study emphasizes the importance of being cautious when using soy protein in infants with cow's milk protein allergy, especially in areas where cost is a major concern.