Inappropriate reaction of immune system mainly to water soluble food proteins

Pathophysiology

• Two main types: immediate hypersensitivity reaction (IgE mediated) and delayed hypersensitivity reaction (non-IgE mediated)
• The 2011 NICE guidelines differentiate between IgE mediated and non-IgE mediated allergies

Clinical presentation

IgE mediated

Skin

• Pruritus
• Erythema
• Urticaria
• Angioedema

Gastrointestinal system

• Nausea
• Colicky abdominal pain
• Vomiting
• Diarrhoea

Respiratory system

• Upper respiratory tract symptoms - nasal itching,sneezing, rhinorrhoea or congestion (with or without conjunctivitis)
• Lower respiratory tract symptoms - cough, chest tightness, wheezing or shortness of breath