Food Allergy Misdiagnosis in Infants & Children Case Reports

Introduction

A case report published in Cureus detailed an infant born at 27 weeks whose symptoms of sepsis and severe metabolic acidosis were ultimately traced to a cow’s milk allergy. Another recent case documented a 2-year-old’s unusual reaction to potato protein. These reports highlight a central challenge: food allergies and intolerances can manifest in ways that mimic other conditions, complicating prevention and diagnosis.

A 960-Gram Preterm Infant’s Diagnosis Offers a Cautionary Tale

In September 2025, physicians at Ibri Hospital in Oman published a case report of an infant whose journey illuminates the diagnostic complexity of food allergies. Born at 27 weeks and four days, weighing 960 grams, the baby experienced persistent feeding problems, poor growth, and respiratory distress. Despite interventions for suspected sepsis and necrotizing enterocolitis, his condition worsened. On day 45, he developed life-threatening metabolic acidosis, a state where the blood becomes dangerously acidic, with a blood pH of 6.815. For reference, a healthy pH is tightly regulated around 7.4. His bicarbonate level was 3.9 mmol/L, far below the normal 22-28 mmol/L.

This dramatic presentation initially pointed doctors toward an inborn error of metabolism. Testing ruled that out. A key detail emerged: the infant was fed expressed breast milk from a mother whose diet included dairy. This meant he was exposed to cow’s milk proteins indirectly. On day 52, the medical team considered cow’s milk allergy (CMA) as a cause. They switched his diet to an extensively hydrolyzed, amino acid-based formula, specifically Neocate. The infant’s response was rapid and definitive. His metabolic imbalance resolved, feeding improved, and he gained 260 grams in just eight days, leading to a successful discharge.

What Severe Allergic Reactions Reveal About Immune Mechanisms

These cases demonstrate how an immune system response can cause systemic chaos. In a classic food allergy, the body’s immune system misidentifies a food protein, like cow’s milk casein or whey, as a threat. It produces Immunoglobulin E (IgE) antibodies, which trigger the release of histamine and other chemicals, causing well-known symptoms like hives or anaphylaxis. However, food protein-induced enterocolitis syndrome (FPIES), a non-IgE mediated allergy, often involves a delayed, severe gastrointestinal and systemic inflammatory response. The preterm infant’s profound metabolic acidosis may reflect this type of reaction, where gut inflammation and damage disrupt the body’s ability to maintain its acid-base balance.

The child with a potato allergy, reported by researchers at the University of Thessaly, presented with atypical symptoms, broadening the spectrum of possible reactions. Such variability means symptoms can be easily attributed to common viral illnesses or, in preterm infants, to complications of prematurity itself. This overlap significantly delays correct diagnosis and treatment. It is a reminder that an allergic reaction is not a single event but a cascade of immune and inflammatory processes that can affect multiple organ systems.

Applying Research to Prevention and Early Detection Strategies

Current evidence supports early introduction of allergenic foods as a preventive measure. Waiting to introduce foods like peanut, egg, or milk past 4-6 months of age may inadvertently increase allergy risk. Guidelines recommend introducing these foods when an infant is developmentally ready, typically around 6 months, and maintaining regular exposure. For a detailed approach, our guide on Introducing Allergenic Foods to Infants offers practical steps.

For high-risk infants, especially those with severe eczema or an existing food allergy, consultation with a pediatrician or allergist before introduction is advised. The Ibri Hospital case also underscores a critical action point for parents and healthcare providers: when an infant, particularly a preterm one, fails to improve with standard treatments for common issues, dietary protein allergy must be considered earlier. An elimination diet, supervised by a doctor, can serve as both a diagnostic tool and a treatment.

Nutritional deficits are a serious risk when feeding problems persist, as they can directly impact growth and neurodevelopment. This connection is explored in our article on Feeding Problems Deplete Nutrients. Ensuring adequate nutrition during an elimination diet is vital; amino acid-based formulas are designed to provide complete nutrition while bypassing the allergic response.

Conclusion

Food allergy prevention hinges on timely, guided introduction of potential allergens. Awareness that reactions can be severe and masquerade as other illnesses is essential for early detection, especially in vulnerable populations. Recognizing these signs and acting swiftly can change a child’s clinical course, as shown by the rapid recovery of the infant in Oman once the correct dietary intervention was made.

Sources:
https://pubmed.ncbi.nlm.nih.gov/41141211/
https://pubmed.ncbi.nlm.nih.gov/40955319/