Continuing Medical Education
Epidemiology of IgE-mediated food allergy
Despite the large number of foods that may cause immunoglobulin E (IgE)-mediated reactions, most prevalence studies have focused on the most common allergenic foods, i.e. cow’s milk, hen’s egg, peanut, tree nut, wheat, soya, fish and shellfish.
Food allergy peaks during the first two years of life, and then diminishes towards late childhood as tolerance to several foods develops. Based on meta-analyses and large population-based studies, the true prevalence of food allergy varies from 1% to >10%, depending on the geographical area and age of the patient.
The prevalence of food allergy in South Africa (SA) is currently being studied. The prevalence of IgE-mediated food allergy in SA children with moderate-to-severe atopic dermatitis is 40%; however, this represents a high-risk population for food allergy. Preliminary data from the South African Food Sensitisation and Food Allergy (SAFFA) study, which is investigating food allergy in an unselected cohort of 1 - 3-year olds, show a prevalence of 11.6% sensitisation to common foods. Food allergy was most common to egg (1.4%) and peanut (1.1%).
Food allergy appears to be the most common trigger of anaphylactic reactions in the community, especially in children, in whom food is responsible for ≥85% of such reactions. In adults, shellfish and nut, and in children, peanut, tree nut, milk and egg, are the most common triggers of food-induced anaphylaxis.
C L Gray, Private Practice, Vincent Pallotti Hospital, Pinelands, Cape Town, South Africa
E Goddard, Division of Paediatric Gastroenterology, Department of Paediatrics and Child Health, Faculty of Health Sciences, University of Cape Town and Red Cross War Memorial Children’s Hospital, Cape Town, South Africa
S Karabus, Private Practice, Christiaan Barnard Memorial Hospital, Cape Town, and Division of Allergy, Department of Paediatrics and Child Health, Faculty of Health Sciences, University of Cape Town and Red Cross War Memorial Children’s Hospital, Cape Town, South Africa
M Kriel, Private Practice, Alberton, Johannesburg, South Africa
A C Lang, Wits Donald Gordon Medical Centre, Johannesburg, South Africa
A I Manjra, Private Practice, Westville, Durban, South Africa
S M Risenga, Department of Pulmonology and Allergy, Faculty of Health Sciences, Polokwane Campus, University of Limpopo, Polokwane, South Africa
A J Terblanche, Department of Paediatrics, Faculty of Health Sciences, University of Pretoria and Steve Biko Academic Hospital, Pretoria, South Africa
D A van der Spuy, Private Practice, Cape Town, South Africa
M E Levin, Division of Allergy, Department of Paediatrics and Child Health, Faculty of Health Sciences, University of Cape Town and Red Cross War Memorial Children’s Hospital, Cape Town, South Africa
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Date published: 2014-11-11
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