Noriyuki Yanagida1, Sakura Sato2, Kyohei Takahashi3, Ken-Ichi Nagakura3, Kiyotake Ogura3, Tomoyuki Asaumi3, Motohiro Ebisawa2. 1. Department of Pediatrics, Sagamihara National Hospital, Kanagawa, Japan. Electronic address: n-yanagida@sagamihara-hosp.gr.jp. 2. Department of Allergy, Clinical Research Center for Allergy and Rheumatology, Sagamihara National Hospital, Kanagawa, Japan. 3. Department of Pediatrics, Sagamihara National Hospital, Kanagawa, Japan.
Abstract
BACKGROUND: Buckwheat (BW) is a potentially life-threatening allergen. Usefulness of BW-specific immunoglobulin-E (BW-sIgE) level for diagnosis of BW allergy is controversial, while the skin prick test (SPT) is widely used because of its less invasive procedure and immediate results. However, there are no data comparing usefulness of the SPT and BW-sIgE level. Therefore, our study aimed to clarify efficacy of the SPT for diagnosis of BW allergy. METHODS: This retrospective cross-sectional study evaluated patients who underwent an oral food challenge (OFC) for diagnosis or confirmation of acquired tolerance using 3072 mg of BW protein between July 2006 and April 2014. We then compared the diagnostic performance of BW sIgE and SPT to predict positive OFC results. RESULTS: We analyzed 126 patients aged 2-16 years (median, 7.7 years), 18 (14%) of whom showed positive OFC results. Between patients with positive and negative OFC results, there was no significant difference in BW-sIgE level. However, patients with positive OFC results had a larger SPT wheal diameter. Area under the curve for positive OFC results for BW-sIgE level and SPT wheal diameter were 0.583 and 0.791, respectively. The 5%, 10%, 50%, and 90% positive predictive values of SPT wheal diameter were 2.0 mm, 5.2 mm, 14.7 mm, and 24.1 mm, respectively. CONCLUSIONS: Our study revealed that the SPT was more useful than BW-sIgE level for diagnosis of BW allergy. Thus, an OFC may be avoided if the patient's SPT wheal diameter is at least 24.1 mm.
BACKGROUND:Buckwheat (BW) is a potentially life-threatening allergen. Usefulness of BW-specific immunoglobulin-E (BW-sIgE) level for diagnosis of BWallergy is controversial, while the skin prick test (SPT) is widely used because of its less invasive procedure and immediate results. However, there are no data comparing usefulness of the SPT and BW-sIgE level. Therefore, our study aimed to clarify efficacy of the SPT for diagnosis of BWallergy. METHODS: This retrospective cross-sectional study evaluated patients who underwent an oral food challenge (OFC) for diagnosis or confirmation of acquired tolerance using 3072 mg of BW protein between July 2006 and April 2014. We then compared the diagnostic performance of BW sIgE and SPT to predict positive OFC results. RESULTS: We analyzed 126 patients aged 2-16 years (median, 7.7 years), 18 (14%) of whom showed positive OFC results. Between patients with positive and negative OFC results, there was no significant difference in BW-sIgE level. However, patients with positive OFC results had a larger SPT wheal diameter. Area under the curve for positive OFC results for BW-sIgE level and SPT wheal diameter were 0.583 and 0.791, respectively. The 5%, 10%, 50%, and 90% positive predictive values of SPT wheal diameter were 2.0 mm, 5.2 mm, 14.7 mm, and 24.1 mm, respectively. CONCLUSIONS: Our study revealed that the SPT was more useful than BW-sIgE level for diagnosis of BWallergy. Thus, an OFC may be avoided if the patient's SPT wheal diameter is at least 24.1 mm.