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Narcolepsy-like sleepiness is a common immediate-type symptom in food allergy

Published: December 16, 2022

Food allergy is a major issue especially in industrialized countries. Food allergic reactions may involve the skin, the gastrointestinal tract, the airways as well as the cardiovascular system. In addition to these typical symptoms, cases have been reported of children who fell asleep and were difficult to wake. For many, it is often hard to distinguish this narcolepsy-like sleepiness from cardiovascular problems with loss of consciousness. In a recent publication in The Journal of Allergy and Clinical Immunology: In Practice, Kalb and colleagues investigated this phenomenon of transient somnolence systematically in a large cohort of children with food allergies. The researchers focused on the frequency, comorbidities, the correlation with certain foods and the severity of reactions.

Data were included from 848 children with challenge-proven food allergy with immediate type symptoms, who had undergone testing for clinical reasons at Charité University hospital. Patient history, especially atopic comorbidities, was obtained from medical records and symptoms occurring during food challenges were documented. This included the occurrence of narcolepsy-like sleepiness within 2 hours after food intake. Narcolepsy-like sleepiness was defined as a somnolent condition during which patients could barely be woken up and which was observed before medication was administered, to exclude sleepiness for iatrogenic causes. Narcolepsy-like sleepiness without other manifestations of an immediate-type allergic reaction was not a stopping criterion for the oral food challenge.

In this large cohort of children with challenge-proven food allergy, Kalb and colleagues were able to characterize narcolepsy-like sleepiness as a symptom affecting 12.5% of food allergic patients. Children with eczema had a higher risk of developing this condition. Narcolepsy-like sleepiness occurred most often due to an allergic reaction to hazelnut or other tree nuts. Moderate to severe reactions occurred more often than mild reactions in children with narcolepsy-like sleepiness. This report is the first systematic characterization of this underestimated symptom, and therefore this study makes a significant contribution to shed light on this neurological symptom and its clinical picture. Nevertheless, further clinical and experimental studies must be conducted to gain a deeper insight into its characteristics and to unravel the underlying mechanisms.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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