Description

• Hypersensitivity reaction caused by certain foods
• System(s) affected: Gastrointestinal; Hemic/Lymphatic/Immunologic; Pulmonary; Skin/Exocrine
• Synonym(s): Allergic bowel disease; Dietary protein-sensitivity syndrome

Epidemiology

• Predominant age: All ages, but more common in infants and children
• Predominant sex: Male > Female (2:1)

Incidence
Prospective studies indicate ~2.5% of infants experience hypersensitivity reactions to cow's milk in their 1st year of life (1)[B].

• The prevalence of IgE-mediated food allergy is likely 1–2% in the US (2,3)[A].
• In young children, the most common food allergies are cow’s milk (2.5%), egg (1.3%), peanut (0.8%), and wheat (0.4%).
• Adults tend to have allergies to shellfish (2%), peanut (0.6%), tree nuts (0.5%), and fish (0.4%) (3)[B].
• In general, only 3–4% of children >4 years have persisting food allergy; it is frequently a transient phenomenon.
• 20% of children with peanut-protein allergy outgrow their sensitivity by school age (3,4)[B].

Risk Factors

• Persons with allergic or atopic predisposition have increased risk of hypersensitivity reaction to food.
• Family history of food hypersensitivity

Genetics
In family members with a history of food hypersensitivity, the probability of food allergy in subsequent siblings may be as high as 50%.

General Prevention

Avoidance of offending food

Pathophysiology

Allergic response owing to immunologic mechanisms, such as the classic IgE-allergic response or nonimmunologic-mediated mechanisms

Etiology

• Any food or ingested substance can cause allergic reactions:
  • Most commonly implicated foods include cow’s milk, egg whites, wheat, soy, peanuts, fish, tree nuts (walnut and pecan), and shellfish
• Several food dyes and additives may elicit allergic like reactions.