Food allergy as seen by a paediatric gastroenterologist.

Approximately 7% to 8% of children are affected by food allergies, the most common being cow's milk allergy (CMA), and egg and peanut allergies. The occurrence of CMA decreases with age, but it is often replaced by other allergic manifestations. CMA affects mainly the skin and gastrointestinal tract, and reactions mediated via immunoglobulin E manifest differently to those that are not. Gastroesophageal reflux disease is frequently present in the first year of life and may be associated with CMA. Eosinophilic oesophagitis is related to food allergy and aeroallergens, less common than gastroesophageal reflux disease, and generally occurs in older children. Eosinophilic oesophagitis manifests as classic symptoms of reflux plus dysphagia. Treatment includes allergen avoidance and local steroid treatment. Other manifestations of CMA include eosinophilic gastroenteritis and proctocolitis. Accurate diagnosis of food allergy and the causative food is important because the condition is present in only about one third of patients with suspected food allergy, may be due to foods other than those originally suspected, and elimination diets may be detrimental to the child's health. Differential diagnosis is important to rule out upper and/or lower gastrointestinal disorders. Food allergy is generally treated with a hypoallergenic diet; antihistamines and leukotriene receptor antagonists may be used in specific conditions.