Pediatric Food Allergy: Recognizing Symptoms and Finding Causes

What is a food allergy in children?

A food allergy in children is an abnormal immune response of the body to certain food components that are typically harmless. It can manifest with a variety of symptoms affecting different body systems. It is important to distinguish a true food allergy from food intolerance, as the mechanisms and approaches to treating these conditions differ.

Variety of symptoms: from skin to digestion

Symptoms of food allergies in children can be very diverse, affecting the skin, gastrointestinal tract, respiratory system, and even manifesting as general systemic reactions. Their severity ranges from mild to life-threatening.

Skin manifestations

• Eczema (atopic dermatitis): Often one of the first manifestations of allergy in infants. Impaired skin barrier in early life is associated with an increased risk of developing both eczema and food allergy [6].
• Urticaria (hives): The appearance of itchy, red welts on the skin.
• Angioedema: Sudden swelling of the lips, eyelids, face, and sometimes the larynx. It is important to note that angioedema can also be of a non-allergic nature, for example, in certain autoimmune thyroid diseases; in this case, it is not accompanied by hives and does not respond to antihistamines [4].

Gastrointestinal symptoms

• Chronic vomiting and frequent regurgitation: May be a sign of a food allergy, but also require the exclusion of other causes [5].
• Recurrent episodes of partial intestinal obstruction: In some cases, conditions such as jejunal atresia may be mistaken for cow's milk protein allergy due to similar symptoms [5].
• Abdominal pain, diarrhea, constipation: These symptoms are frequent manifestations of food allergies. However, they can also occur as side effects of certain diets, such as ketogenic therapy in infants [2].
• Functional gastrointestinal disorders (FGIDs): Although they may share similar symptoms, a study found no association between antibiotic use in the first week of life and the development of FGIDs or food allergy at 9-12 years of age [3].

General symptoms

• Growth and developmental delay, failure to thrive: Chronic gastrointestinal problems caused by food allergies can lead to nutrient malabsorption and, consequently, delayed physical development [5].
• Elevated eosinophils and total IgE: These laboratory markers often indicate an allergic reaction, although they can also be elevated in other conditions [4].

When symptoms are not allergy-related: important differential diagnosis

Symptoms resembling a food allergy can be caused by numerous other conditions. It is important not to rush into an "allergy" diagnosis, especially if symptoms do not respond to standard treatment, and to conduct a thorough differential diagnosis.

• Structural GI anomalies: Chronic vomiting, bowel problems, and growth delay can be caused by congenital malformations such as jejunal atresia or congenital fibrous bands, which may be mistaken for cow's milk protein allergy [5].
• Celiac disease: This is not an allergy, but an autoimmune disease triggered by gluten. It can manifest not only with gastrointestinal symptoms (abdominal pain, diarrhea, growth delay) but also with a wide range of neurological and psychiatric disorders [7].
• Autoimmune diseases: For example, autoimmune thyroid diseases can cause angioedema without hives, which is not allergy-related and requires specific treatment with levothyroxine [4].
• Functional gastrointestinal disorders (FGDs): These conditions, such as irritable bowel syndrome, can cause similar symptoms but have no organic cause.

Risk factors and prevention

• Impaired skin barrier: Infants with an impaired skin barrier (e.g., with eczema) have an increased risk of developing both eczema and food allergy. The use of skincare products such as emollients may be effective in preventing eczema, but its impact on food allergy prevention requires further research [6].
• Early childhood antibiotics: Contrary to the common belief about the link between early antibiotic use and allergy development, a recent study found no association between antibiotic use in the first week of life and the development of functional gastrointestinal disorders or food allergies at 9-12 years of age [3].

Diagnosis and treatment

Diagnosing food allergies in children is a comprehensive process that should be carried out under the supervision of a specialist. It includes a thorough medical history, physical examination, keeping a food diary, elimination diets followed by a food challenge (under medical supervision), as well as skin prick tests and blood tests for specific IgE antibodies. In some cases, additional studies may be required to rule out other diseases.

The treatment of food allergies is based on the strict elimination of the allergen from the child's diet. Consultation with an allergist-immunologist and a nutritionist is important to ensure adequate and balanced nutrition, especially in children with multiple food allergies or during periods of active growth.

Sources

1. Antibiotics in the first week of life are not associated with functional gastrointestinal disorders at 9-12 years of age. (Journal of pediatric gastroenterology and nutrition, 2026)
2. Pediatric angioedema without urticaria: A rare manifestation of autoimmune thyroid disease with complete remission on levothyroxine therapy. (Journal of postgraduate medicine, 2025)
3. Delayed diagnosis of type I jejunal atresia in an infant with intractable vomiting: A case report. (Journal of surgical case reports, 2025)
4. Skincare interventions in infants for preventing eczema and food allergy. (The Cochrane database of systematic reviews, 2022)
5. Celiac disease as a model of gut-brain autoimmunity: From gluten exposure to neuropsychiatric manifestations. (Frontiers in pediatrics, 2026)
6. Efficacy, safety, and growth impact of ketogenic diet therapy in children under two years of age. (European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society, 2026)

Disclaimer: The information provided in this article is for reference purposes only and should not be used for self-diagnosis or self-treatment. Always consult a qualified medical professional for an accurate diagnosis and an individualized treatment plan.