Food Allergy (Pediatric)

Food allergy in children is an adverse immune-mediated reaction to specific dietary proteins, leading to a range of clinical symptoms from mild cutaneous manifestations to life-threatening anaphylaxis.

Definition

Epidemiology

Prevalence in children is approximately 6–8% worldwide
Most common in infants and young children; some allergies resolve with age
Common allergens include milk, eggs, peanuts, tree nuts, soy, wheat, fish, and shellfish
Family history of atopy increases risk
Higher prevalence in children with eczema, asthma, or allergic rhinitis

Etiology

IgE-mediated hypersensitivity to specific food proteins
Non-IgE-mediated or mixed immune reactions (e.g., food protein-induced enterocolitis syndrome)
Genetic predisposition to atopy
Environmental factors and early dietary exposures
Cross-reactivity between related food allergens (e.g., peanuts and tree nuts)

Pathophysiology

Sensitization occurs when the immune system recognizes food proteins as antigens
IgE antibodies bind to mast cells and basophils
Upon re-exposure, cross-linking of IgE triggers degranulation, releasing histamine and other mediators
Leads to vasodilation, increased vascular permeability, smooth muscle contraction, and inflammation
Non-IgE mechanisms involve T-cell-mediated responses causing delayed gastrointestinal or cutaneous symptoms
Severe reactions may progress to systemic anaphylaxis with airway compromise and hypotension