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Physician Advice and Action Plans in Severe Food Allergy
Analysis of Placebo Reactions in Double-Blind, Placebo-Controlled Food Challenge Tests in Children B. J. Vlieg-Boerstra1, S. van der Heide2, J. Kukler1, C. M. A. Bijleveld1, B. J. Beusekamp3, E. J. Duiverman1, A. E. J. Dubois4; 1Dept. of Paediatrics, University Medical Center Groningen, University of Groningen, Groningen, THE NETHERLANDS, 2Dept. of Allergology, University Medical Center Groningen, University of Groningen, Groningen, THE NETHERLANDS, 3Dept. of Dietetics, University Medical Center Groningen, University of Groningen, Groningen, THE NETHERLANDS, 4Dept of Allergology and Dept of Paediatrics, University Medical Center Groningen, University of Groningen, Groningen, THE NETHERLANDS. RATIONALE: Although it is generally accepted that the double-blind, placebo-controlled food challenge (DBPCFC) is the gold standard in the diagnosis of food allergy, to date, the occurrence and importance of placebo challenges has not extensively been documented. The purpose of this study was to analyze the occurrence of placebo reactions in DBPCFCs in children. METHODS: The study population consisted of 141 DBPCFCs in 115 children (age range 0,5 -16,6 years, median 5,5 years), who consecutively underwent DBPCFCs between January 2004 and May 2005 with cow’s milk (58x), egg (28x), peanut (32x), hazelnut (14x) and soy (9x). Active and placebo challenges were separated by at least two weeks. An algorithm was devised to assess reactions following challenges and to classify the outcome of DBPCFCs in a uniform fashion. RESULTS: 57/141 DBPCFCs (40 %) were clear cut positive: in 46 of these children immediate reactions occurred, and in 11 of these children delayed symptoms observed by the parents were assessed as positive. In 22 children (16%) placebo reactions occurred: 10 of these 22 children reacted with immediate reactions, of whom 2 children were under 3 years of age. 12 of these 22 placebo reactions consisted of delayed symptoms only observed by the parents. Inclusion of the placebo in evaluating the DBPCFCs allowed for identification of 7/64 (11%) positive reactions to the active challenge as being false positive. CONCLUSIONS: Inclusion of placebos contributes to the diagnostic accuracy of DBPCFCs. Placebo reactions occur in 16% of all cases. Placebo reactions also occur in young children, albeit less frequently. Funding: University Medical Center Groningen
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Physician Advice and Action Plans in Severe Food Allergy
J. S. W. Kong1, L. A. D. Haapanen1, L. J. Phillipo2, C. M. Bruhn2, S. S. Teuber1; 1Rheumatology, Allergy, and Clinical Immunology, University of California at Davis, Davis, CA, 2Food Science and Technology, University of California at Davis, Davis, CA. RATIONALE: Food allergies afflict 2-3% of adults. This study aimed to identify physician advice related to implementation of action plans for severe food allergies. METHODS: A structured, 123-item interview administered to adults with food allergies. RESULTS: 29 patients were interviewed. All had severe reactions to food including laryngeal/pharyngeal edema, bronchospasm, or hypotension.
Only 20/29 (69%) patients sought emergency care. 14 of these 20 (70%) were prescribed epinephrine autoinjectors (EAIs). 7/9 people who did not seek acute care also received EAIs. 9/21 (43%) have used their EAI subsequently. Of the 21, 76% were trained to use EAIs, but 29% stored the medication in the car; 68% demonstrated correct use. Only 10% stated their doctor reviews how to use it. Only 24% said their doctor discusses the need to renew EAIs. 85% of patients said that doctors told them to use antihistamines in the treatment of future reactions: in 7/29 (24%) as the sole treatment, and in 6/29 (21%) before using epinephrine. Interestingly, 32% of patients with EAIs did not think their current doctor was aware of the severity of their food allergy. Out of 20 patients with a reported plan of action for future severe reactions, only 45% would use epinephrine, 55% would go to an emergency department, and 70% would take antihistamines. CONCLUSIONS: Patients report a lack of follow-up regarding the role of EAIs by their doctors, in addition to an emphasis on antihistamine use, which may be reflected in the low planned use of EAIs in future severe allergic reactions. Funding: USDA Tropomyosin: Is it Responsible for the Cross-Reactivity Crustaceans-Dust Mites A. Mendes, M. C. Santos, E. Pedro, M. A. Pereira-Barbosa; Unidade Imunoalergologia, Hospital Santa Maria, Lisboa, PORTUGAL. RATIONALE: The aim of the study is to demonstrate that tropomyosin is a panallergen responsible for the cross-reactivity crustaceans-dust mites. METHODS: We studied 10 patients, 5 allergic to crustaceans (3 with cocomitant persistent mild rhinitis - group 1, and 2 without - group 2) and 5 with dust mite allergy and no food allergy. Measurement of serum specific IgE antibodies for Dermatophagoides pteronyssinus (d1), lobster (f80), shrimp (f24), crab (f23) and tropomyosin (Rf351) were made in all patients. RAST-inhibition tests were performed between all allergens in those patients with a positive specific IgE for Rf 351. RESULTS: Measurement of specific IgE was positive for d1, f80, f24, f23 and Rf 351 in patients with crustaceans allergy, while in those with dust mite allergy only d1 was positive. Inhibition tests within group 1 showed that for serum incubated with f24 extract inhibition rate was >80% for f24, f23 and f80 and >60% for d1. Similar results were obtained with f23 and f80. In serum incubated with d1 inhibition rate was of 100% for d1 and >70% for f24, f23 and f80. Serum incubated with f24, f23, f80 and d1 showed an inhibition rate >80% for Rf351. Serum incubated with Rf351 extract showed an inhibition rate of 100% for Rf351, f24, f80, f23 and >50% for d1. Inhibition rates were slightly lower within group 2. CONCLUSIONS: Tropomyosin is an important allergen in crustaceans and a minor one in dust mites. This supports the hypothesis that tropomyosin is responsible for the cross-reactivity crustaceans-dust mites.
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Abstracts S51
J ALLERGY CLIN IMMUNOL VOLUME 117, NUMBER 2
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Physician Advice and Action Plans in Severe Food Allergy
J. S. W. Kong1, L. A. D. Haapanen1, L. J. Phillipo2, C. M. Bruhn2, S. S. Teuber1; 1Rheumatology, Allergy, and Clinical Immunology, University of California at Davis, Davis, CA, 2Food Science and Technology, University of California at Davis, Davis, CA. RATIONALE: Food allergies afflict 2-3% of adults. This study aimed to identify physician advice related to implementation of action plans for severe food allergies. METHODS: A structured, 123-item interview administered to adults with food allergies. RESULTS: 29 patients were interviewed. All had severe reactions to food including laryngeal/pharyngeal edema, bronchospasm, or hypotension.
Only 20/29 (69%) patients sought emergency care. 14 of these 20 (70%) were prescribed epinephrine autoinjectors (EAIs). 7/9 people who did not seek acute care also received EAIs. 9/21 (43%) have used their EAI subsequently. Of the 21, 76% were trained to use EAIs, but 29% stored the medication in the car; 68% demonstrated correct use. Only 10% stated their doctor reviews how to use it. Only 24% said their doctor discusses the need to renew EAIs. 85% of patients said that doctors told them to use antihistamines in the treatment of future reactions: in 7/29 (24%) as the sole treatment, and in 6/29 (21%) before using epinephrine. Interestingly, 32% of patients with EAIs did not think their current doctor was aware of the severity of their food allergy. Out of 20 patients with a reported plan of action for future severe reactions, only 45% would use epinephrine, 55% would go to an emergency department, and 70% would take antihistamines. CONCLUSIONS: Patients report a lack of follow-up regarding the role of EAIs by their doctors, in addition to an emphasis on antihistamine use, which may be reflected in the low planned use of EAIs in future severe allergic reactions. Funding: USDA Tropomyosin: Is it Responsible for the Cross-Reactivity Crustaceans-Dust Mites A. Mendes, M. C. Santos, E. Pedro, M. A. Pereira-Barbosa; Unidade Imunoalergologia, Hospital Santa Maria, Lisboa, PORTUGAL. RATIONALE: The aim of the study is to demonstrate that tropomyosin is a panallergen responsible for the cross-reactivity crustaceans-dust mites. METHODS: We studied 10 patients, 5 allergic to crustaceans (3 with cocomitant persistent mild rhinitis - group 1, and 2 without - group 2) and 5 with dust mite allergy and no food allergy. Measurement of serum specific IgE antibodies for Dermatophagoides pteronyssinus (d1), lobster (f80), shrimp (f24), crab (f23) and tropomyosin (Rf351) were made in all patients. RAST-inhibition tests were performed between all allergens in those patients with a positive specific IgE for Rf 351. RESULTS: Measurement of specific IgE was positive for d1, f80, f24, f23 and Rf 351 in patients with crustaceans allergy, while in those with dust mite allergy only d1 was positive. Inhibition tests within group 1 showed that for serum incubated with f24 extract inhibition rate was >80% for f24, f23 and f80 and >60% for d1. Similar results were obtained with f23 and f80. In serum incubated with d1 inhibition rate was of 100% for d1 and >70% for f24, f23 and f80. Serum incubated with f24, f23, f80 and d1 showed an inhibition rate >80% for Rf351. Serum incubated with Rf351 extract showed an inhibition rate of 100% for Rf351, f24, f80, f23 and >50% for d1. Inhibition rates were slightly lower within group 2. CONCLUSIONS: Tropomyosin is an important allergen in crustaceans and a minor one in dust mites. This supports the hypothesis that tropomyosin is responsible for the cross-reactivity crustaceans-dust mites.
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Abstracts S51
J ALLERGY CLIN IMMUNOL VOLUME 117, NUMBER 2