Macadamia nut‐specific IgE levels for predicting anaphylaxis

Abstract

Background Despite the high risk of anaphylaxis in patients with a macadamia nut allergy (MdA), little is known about the significance of macadamia nut‐specific immunoglobulin E (Md‐sIgE). Thus, this study aimed to investigate the utility of Md‐sIgE for predicting anaphylaxis. Methods Children with suspected MdA who visited our hospital were included. MdA was defined as either failing the 3‐g macadamia nut (Md) oral food challenge (OFC) or confirming obvious immediate symptoms following Md ingestion. Non‐MdA was defined as passing the 3‐g Md OFC. Results A total of 41 children (29 [71%] males) with a median age of 7.7 years were included. The median Md‐sIgE level was 2.23 kUA/L. Among the 21 children diagnosed with MdA, eight and 13 children did (An group) and did not (non‐An group) develop anaphylaxis. Twenty children were included in the non‐MdA group. The Md‐sIgE level was significantly higher in the An group relative to the others (7.97 vs. 1.92 kUA/L, p < .001). Furthermore, the Md‐sIgE level was significantly higher in the An group than in the non‐An group (7.97 vs. 1.92 kUA/L, p = .02). However, there was no significant difference in the Md‐sIgE between the non‐An and non‐MdA groups (1.92 vs. 1.90 kUA/L, p > .99). The area under the curve for predicting anaphylaxis in Md‐sIgE was 0.92 (95% CI: 0.83–1.00), and the optimal cut‐off value was 3.76 kUA/L. Conclusion Md‐sIgE levels were useful in predicting anaphylaxis. Above the cut‐off value, we emphasize paying careful attention to the risk of anaphylaxis.

Macadamia Nut-Induced Anaphylactic Shock Requiring Repeated Intramuscular Adrenaline Administration in a Three-Year-Old Girl

“…However, the measurement of IgE specific to macadamia nuts does not always predict clinical allergy and may lead to false-negative results [ 2 ]. The cutoff value for predicting anaphylaxis by macadamia nut-specific IgE testing was >3.76 UA/mL [ 13 ]. However, the current case report reported a cut-off value of 1.26 UA/mL, indicating that the macadamia nut-specific IgE value may not always predict anaphylaxis in certain patients.…”