Soy protein intolerance: four patients with concomitant cow's milk intolerance

Area of Science:

• Pediatric Gastroenterology
• Allergy and Immunology
• Infant Nutrition

Background:

• Gastrointestinal soy protein intolerance is an uncommon and poorly understood infantile disorder.
• Intractable diarrhea of infancy and failure to thrive are significant clinical challenges in affected infants.

Observation:

• Four infants with intractable diarrhea and failure to thrive were evaluated.
• Oral challenge with soy protein isolate induced immediate, short-lived symptoms including diarrhea, vomiting, hypotension, lethargy, and fever in all four patients.
• All patients also demonstrated sensitivity to cow's milk protein.

Findings:

• Confirmed diagnosis of soy protein intolerance in four infants.
• Symptoms were reproducible upon subsequent oral challenges with soy protein.
• No cutaneous, pulmonary, or hematologic allergic reactions were observed, despite family history.

Implications:

• A diet excluding intact soy and cow's milk protein led to symptomatic recovery and improved weight gain.
• Oral disodium cromoglycate was ineffective in one patient.
• Clinicians should consider soy protein intolerance in infants with intractable diarrhea unresponsive to standard soy-based formulas.