Peanut and Tree Nut Allergy in A Country with Low Prevalence: Clinical Characteristics, Associated Factors and Sensitization Patterns with Other Nuts and Legumes

Abstract

RATIONALE: Prevalence of peanut (PN) and tree nut (TN) allergy in Asian countries is low compared with western countries. We aimed to identify clinical characteristics, associated factors and sensitization patterns in Thailand, a country with low prevalence.METHODS: Patients with peanut allergy (PA) and/or tree nut allergy (TA) were enrolled. Data on clinical characteristics and sensitization to PN, TN and legumes were analyzed.RESULTS: Twenty-three subjects with PA and 8 subjects with TA were included. Two distinct populations of PA were identified; early vs late onset (n=18 vs 5, mean age of onset 20 months vs 13 years). Most had multiple food allergies (75%) and were from high socio-economic status (90%). Ninety percents of early-onset patients reported symptoms on first exposure with roasted peanuts (67%) and boiled peanuts (33%). The early-onset group was associated with atopic dermatitis, had less severe reactions but higher peanut specific IgE (mean 17.33 vs 0.64 kUA/L; P=0.027). TA had older age of onset (17.6 years) and more severe reactions than PA. Twenty and sixty-three percents of PA and TA were born or had lived in western countries. Sensitization pattern in patients with PA was as followed: TN =85%, soybean =47%, other legumes= 37.5% and coconut and sesame each =5.3%. Patients with TA were sensitized to other TN and PN in 80% and 25% respectively.CONCLUSIONS: PA and TA from a country with very low prevalence were characterized by the association with atopic dermatitis, multiple food allergy and high socio-economic status. Co-sensitization between peanut and tree nut were common. RATIONALE: Prevalence of peanut (PN) and tree nut (TN) allergy in Asian countries is low compared with western countries. We aimed to identify clinical characteristics, associated factors and sensitization patterns in Thailand, a country with low prevalence. METHODS: Patients with peanut allergy (PA) and/or tree nut allergy (TA) were enrolled. Data on clinical characteristics and sensitization to PN, TN and legumes were analyzed. RESULTS: Twenty-three subjects with PA and 8 subjects with TA were included. Two distinct populations of PA were identified; early vs late onset (n=18 vs 5, mean age of onset 20 months vs 13 years). Most had multiple food allergies (75%) and were from high socio-economic status (90%). Ninety percents of early-onset patients reported symptoms on first exposure with roasted peanuts (67%) and boiled peanuts (33%). The early-onset group was associated with atopic dermatitis, had less severe reactions but higher peanut specific IgE (mean 17.33 vs 0.64 kUA/L; P=0.027). TA had older age of onset (17.6 years) and more severe reactions than PA. Twenty and sixty-three percents of PA and TA were born or had lived in western countries. Sensitization pattern in patients with PA was as followed: TN =85%, soybean =47%, other legumes= 37.5% and coconut and sesame each =5.3%. Patients with TA were sensitized to other TN and PN in 80% and 25% respectively. CONCLUSIONS: PA and TA from a country with very low prevalence were characterized by the association with atopic dermatitis, multiple food allergy and high socio-economic status. Co-sensitization between peanut and tree nut were common.