Comparison of Diagnostic Tests with Oral Food Challenge in a Clinical Trial for Adult Patients with Sesame Anaphylaxis

Sesame food allergy (SFA); especially anaphylaxis, is a life-threatening condition. The accurate diagnosis of SFA is done by skin prick test (SPT), skin prick to prick (SPP) or specific IgE (sIgE) and is confirmed by oral food challenge (OFC). Since there are few studies evaluating and comparing the utility of these methods for diagnosis of sesame anaphylaxis in adult patients, we aimed to compare OFC with diagnostic tests, including SPT, SPP, and sesames IgE; using ImmunoCAP considering the sensitivity and specificity issues in patients with sesame anaphylaxis. Twenty patients with sesame anaphylaxis were diagnosed based on OFC. Then SPT, SPP, and sIgE were evaluated. Sixteen patients had positive OFC; while 4 patients had negative results. Out of 16 OFC+ patients, 7 patients were SPT+, 15 patients were SPP+, and 2 patients had detectable sIgE. A positive SPT indicated 44% sensitivity and 50% specificity. A positive SPP showed 87.5% sensitivity and 75% specificity. A positive ImmunoCAP test demonstrated 12.5% sensitivity and 75% specificity. The AUC of SPP was significant for the diagnosis of sesame anaphylaxis (p=0.038). In conclusion, when the OFC is not possible, the SPP test with natural sesame seed may be applicable in patients with a convincing history instead of the artificial or commercial extracts of sesame used for SPT. Positive SPP is a good alternative diagnostic method for patients with sesame anaphylaxis. Also, the poor sensitivity of SPT and sIgE may indicate the poor discriminative capability of these tests.