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Medline ® Abstracts for References 21,22

of 'Oral food challenges for diagnosis and management of food allergies'

The eliciting dose of peanut in double-blind, placebo-controlled food challenges decreases with increasing age and specific IgE level in children and young adults.
van der Zee T, Dubois A, Kerkhof M, van der Heide S, Vlieg-Boerstra B
J Allergy Clin Immunol. 2011 Nov;128(5):1031-6. Epub 2011 Aug 31.
BACKGROUND: Several risk factors for severe anaphylactic reactions to food in daily life are known. However, to date, it is not possible to predict the severity of allergic reactions to food in the individual patient with accuracy. Some studies show that a history of severe reactions is associated with a lower eliciting dose in double-blind, placebo-controlled food challenges (DBPCFCs). Therefore, in this study, the eliciting dose was used as a measure of clinical sensitivity.
OBJECTIVES: To study whether risk factors for severe allergic reactions to food in daily life such as age, degree of sensitization, and coexistent atopic disease influence the eliciting dose in DBPCFCs in children allergic to peanut.
METHODS: Data from children who had clinical reactions to peanut during DBPCFCs at the University Medical Center Groningen (2001-2009) were analyzed. A Cox regression model was used to analyze the association of the determinants with the eliciting dose.
RESULTS: One hundred twenty-six positive DBPCFCs with peanut were analyzed. Age older than 10 years, a specific IgE level above the lowest tertile (≥5.6 kU/L), and the absence of atopic dermatitis were associated with reactions to lower doses: respective hazard ratios 1.89 (95% CI, 1.28-2.81; P = .001), 2.03 (95% CI, 1.37-3.00; P<.0001), and 0.45 (95% CI, 0.29-0.71; P = .001) present versus absent. No significant associations with the eliciting dose were found for sex, the presence of asthma and rhinitis, and the severity of food reactions by history.
CONCLUSIONS: Using the eliciting dose as a measure of clinical sensitivity, greater clinical sensitivity in DBPCFCs to peanut was found to be associated with increasing age, higher specific IgE level, and the absence of atopic dermatitis. This finding may explain why adolescents experience severe allergic reactions in daily life to peanut more often than do younger children.
Department of Paediatric Pulmonology and Allergy, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Factors predicting anaphylaxis to peanuts and tree nuts in patients referred to a specialist center.
Summers CW, Pumphrey RS, Woods CN, McDowell G, Pemberton PW, Arkwright PD
J Allergy Clin Immunol. 2008;121(3):632. Epub 2008 Jan 18.
BACKGROUND: Although acute allergic reactions after ingestion of peanuts and tree nuts are common, fatalities are rare. Other than patients with coexisting asthma, it is currently not possible to predict which patients are most likely to develop severe reactions.
OBJECTIVE: The aim of this study was to determine which clinical and laboratory parameters best predict the likelihood of severe allergic reactions.
METHODS: From 1992 to 2004, we collected detailed information on the clinical severity and allergy test results of 1094 patients with peanut and tree nut allergy attending a regional allergy center. In a subgroup of 122 patients, sera were assayed for activity of enzymes involved in the catabolism of bradykinin.
RESULTS: Severe pharyngeal edema was 3.8 (2.1-6.9) times more common in patients with severe rhinitis and 2.6 (1.8-3.7) more common after ingestion of tree nuts compared with peanuts. Patients with serum angiotensin-converting enzyme concentrations<37.0 mmol/L had a 9.6 (1.6-57)-fold risk of severe pharyngeal edema. Life-threatening bronchospasm was most likely in patients with severe asthma (relative risk, 6.8 [4.1-11.3]) and less so in patients with milder asthma (2.7 [1.7-4.0]). Altered levels of consciousness were more likely in patients with severe eczema (3.1 [1.1-8.4]).
CONCLUSION: Severity of coexisting atopic diseases predicted which patients attending a tertiary referral clinic were most likely to develop life-threatening allergic reactions to peanuts and tree nuts. Patients with the lowest serum angiotensin-converting enzyme concentrations were more likely to develop life-threatening pharyngeal edema, suggesting that this complication may be partly mediated by bradykinin.
Department of Immunology, University of Manchester, Manchester Royal Infirmary, Manchester, United Kingdom.