Banana anaphylaxis in Thailand: case series

Background Banana fruit has been recognized as an important food allergen source. Nowadays banana hypersensitivity had been reported more frequently with various presentations from oral allergy syndrome to anaphylaxis. Objective This study aims to describe the pattern of banana hypersensitivity and the sensitivity of diagnostic test. Methods Six patients who experienced banana hypersensitivity were recruited from adult allergy clinic, Ramathibodi Hospital, Mahidol University between 2015–2018. Demographic data, pattern of banana allergy consisted of the onset of reaction, symptoms, severity, cross-reactivity to kiwi, avocado, latex including type and amount of banana were collected. Skin test, serum specific IgE to banana and open-label food challenge test had been applied. Results All patients experienced multiple episodes of banana anaphylaxis. Regarding the diagnostic investigation, prick-to-prick skin test had higher sensitivity (sensitivity, 100%; 95% confidence interval [CI], 54.07%–100%) than the commercial banana extract (sensitivity, 83.33%; 95% CI, 35.88%–99.58%) and serum specific IgE to banana (sensitivity, 50%; 95% CI, 11.81%–88.19%). The discordance between skin prick test using commercial banana extract and skin test was reported. The cross-reactivity between the species of banana, kiwi, the avocado was documented in all patients. Latex skin prick test and application test were applied with negative results. From the oral food challenge test, a case of banana anaphylaxis patient can tolerate heated banana. Conclusion The various phenotypes of banana hypersensitivity were identified. The prick-to-prick test showed the highest sensitivity for diagnosis of banana allergy. However, component resolved diagnostics might be needed for conclusive diagnosis.