Rural and urban food allergy prevalence from the South African Food Allergy (SAFFA) study

Published:August 07, 2018DOI:


      Food sensitization and challenge-proved food allergy (FA) have not been compared in urban and rural settings.


      We sought to determine and compare the prevalence of food sensitization and challenge-proved IgE-mediated FA in urban and rural South African toddlers aged 12 to 36 months.


      This cross-sectional study of unselected children included 1185 participants in urban Cape Town and 398 in the rural Eastern Cape. All participants completed a questionnaire and underwent skin prick tests (SPTs) to egg, peanut, cow's milk, fish, soya, wheat, and hazelnut. Participants with SPT responses of 1 mm or greater to 1 or more foods and not tolerant on history underwent an open oral food challenge.


      The prevalence of FA was 2.5% (95% CI, 1.6% to 3.3%) in urban children, most commonly to raw egg white (1.9%), followed by cooked egg (0.8%), peanut (0.8%), cow's milk (0.1%), and fish (0.1%). Urban sensitization (SPT response ≥1 mm) to any food was 11.4% (95% CI, 9.6% to 13.3%) and 9.0% (95% CI, 7.5% to 10.8%) at an SPT response of 3 mm or greater. Sensitization in rural cohorts was significantly lower than in the urban cohort (1-mm SPT response, 4.5% [95% CI, 2.5% to 6.6%]; 3-mm SPT response, 2.8% [95% CI, 1.4% to 4.9%]; P < .01). In the rural black African cohort 0.5% (95% CI, 0.1% to 1.8%) of children had food allergy, all to egg. This is significantly lower than the prevalence of the urban cohort overall (2.5%) and urban black African participants (2.9%; 95% CI, 1.5% to 4.3%; P = .006).


      FA prevalence in Cape Town is comparable with rates in industrialized middle-income countries and is significantly greater than in rural areas. Further analysis will describe and compare environmental exposures and other risk factors in this cohort.

      Key words

      Abbreviations used:

      BA (Black African), ECD (Early child development), FA (Food allergy), FS (Food sensitization), MA (Mixed ancestry), OFC (Oral food challenge), SPT (Skin prick test)
      To read this article in full you will need to make a payment


      Subscribe to Journal of Allergy and Clinical Immunology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Levin M.E.
        • Gray C.L.
        • Marrugo J.
        Food allergy: international and developing world perspectives.
        Curr Pediatr Rep. 2016; 4: 129-137
        • Walkner M.
        • Warren C.
        • Gupta R.S.
        Quality of life in food allergy patients and their families.
        Pediatr Clin North Am. 2015; 62: 1453-1461
        • Liu A.H.
        • Jaramillo R.
        • Sicherer S.H.
        • Wood R.A.
        • Bock S.A.
        • Burks A.W.
        • et al.
        National prevalence and risk factors for food allergy and relationship to asthma: results from the National Health and Nutrition Examination Survey 2005-2006.
        J Allergy Clin Immunol. 2010; 126: 798-806.e14
        • Allen K.J.
        • Koplin J.J.
        Why does Australia appear to have the highest rates of food allergy?.
        Pediatr Clin North Am. 2015; 62: 1441-1451
        • Zar H.J.
        • Ehrlich R.I.
        • Workman L.
        • Weinberg E.G.
        The changing prevalence of asthma, allergic rhinitis and atopic eczema in African adolescents from 1995 to 2002.
        Pediatr Allergy Immunol. 2007; 18: 560-565
        • Levin M.E.
        • Muloiwa R.
        • Motala C.
        Associations between asthma and bronchial hyper-responsiveness with allergy and atopy phenotypes in urban black South African teenagers.
        South African Med J. 2011; 101: 472-476
        • Keet C.A.
        • Savage J.H.
        • Seopaul S.
        • Peng R.D.
        • Wood R.A.
        • Matsui E.C.
        Temporal trends and racial/ethnic disparity in self-reported pediatric food allergy in the United States.
        Ann Allergy Asthma Immunol. 2014; 112: 222-229
        • Basera W.
        • Botha M.
        • Gray C.L.
        • Lunjani N.
        • Watkins A.S.
        • Venter C.
        • et al.
        The South African Food Sensitisation and Food Allergy population-based study of IgE-mediated food allergy: validity, safety, and acceptability.
        Ann Allergy Asthma Immunol. 2015; 115: 113-119
        • Matsui E.C.
        • Keet C.A.
        Weighing the evidence: bias and confounding in epidemiologic studies in allergy/immunology.
        J Allergy Clin Immunol. 2017; 139: 448-450