<p><b><i>Background:</i></b> Cashew nuts (CN) are capable of causing
severe allergic reactions. However, little has been reported about the
details of CN oral food challenges (OFC). <b><i>Methods:</i></b>
CN-specific IgE (sIgE) levels were measured for 1 year in 66 patients
who underwent an OFC with >3 g CN for diagnosis or confirmation of
tolerance acquisition between June 2006 and August 2014. We
retrospectively analyzed the OFC and patient background. <b><i>Results:</i></b>
The median (IQR) age of the 66 patients (48 boys/men and 18
girls/women) was 7.0 years (5.7-8.8). Twelve patients (18.2%) had a
positive OFC result; 6 of 8 (75%) patients with a history of an
immediate reaction to CN failed the OFC. Anaphylaxis was experienced by 5
of these 12 (42%) patients. A history of an immediate reaction to CN
and the CN sIgE levels were significantly different for patients with a
positive or negative OFC result (<i>p</i> < 0.01). Among patients
without a previous immediate reaction to CN, the 95% positive predictive
value (PPV) for the CN sIgE level for a positive OFC result was 66.1 kU<sub>A</sub>/L. <b><i>Conclusions:</i></b>
A history of an immediate reaction to CN and high CN sIgE were risk
factors for a positive OFC result. The number of positive OFC results
was relatively low, but there was a high probability of anaphylaxis. We
should consider the indication of OFC carefully for patients with a
history of immediate reactions to CN and avoid OFC for patients without
such a history whose CN sIgE values are >66.1 kU<sub>A</sub>/L (95% PPV).</p
