Medline ® Abstracts for References 22,23
of 'Oral food challenges for diagnosis and management of food allergies'
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.
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-convertingenzyme 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.
Use of Specific IgE and Skin Prick Test to Determine Clinical Reaction Severity.
Ta V, Weldon B, Yu G, Humblet O, Neale-May S, Nadeau K
Br J Med Med Res. 2011;1(4):410-429.
AIMS: To determine whether specific IgE and skin prick test correlate better in predicting reaction severity during a double-blinded placebo controlled food challenge (DBPCFC) for egg, milk, and multiple tree nut allergens. STUDY DESIGN: Prospective study. PLACE AND DURATION OF STUDY: Department of Pediatrics, Stanford University School of Medicine, August 2009 and ongoing. METHODOLOGY: We examined the reaction severity of twenty-four subjects to nine possible food allergens: milk, egg, almond, cashew, hazelnut, peanut, sesame, pecan and walnut. Specific IgE and SPT were performed before each DBPCFC. DBPCFC results were classified into mild (1), moderate (2), or severe (3) reactions using a modified Bock's criteria. RESULTS: Twenty four subjects underwent a total of 80 DBPCFC. Eighty percent of all DBPCFCs resulted in a positive reaction. A majority, 71%, were classified as mild. No reactions occurred with a SPT of zero mm while three reactions occurred with a negative specific IgE. All reactions were reversible with medication. CONCLUSION: These data suggest that SPT and specific IgE levels are not associated with reaction severity (p<0.64 and 0.27, respectively). We also found that combining specific IgE and SPT improved specificity but did not help to achieve clinically useful sensitivity. For instance, an SPT>5mm had a sensitivity of 91%and specificity of 50%. Combining SPT>5mm and IgE>7 resulted in a reduced sensitivity of 64%. Unexpectedly, a history of anaphylaxis 70% (n=17) was not predictive of anaphylaxis on challenge 4% (n=2).
2351 Clay Street, Suite 380, San Francisco, CA 94115, Department of Internal Medicine, California Pacific Medical Center, California, United States.