HealthDay News — The circadian clock seems to have a significant impact on allergic reaction, according to results of a study published in Allergy.

“Given the strong influence of circadian rhythms on allergic diseases, we believe that research on how the time of day impacts allergic reaction which we may call ‘chronoallergology’ will provide new insight into previously unknown aspects of the biology of allergies,” explained Atsuhito Nakao, MD, PhD, of the University of Yamanashi in Japan, and colleagues.

To examine the emerging role of the circadian clock as a regulator of allergic reactions, the investigators reviewed existing medical literature.

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Symptoms and laboratory parameters of allergic disease exhibit prominent circadian variations, with symptoms worsening overnight or early in the morning in allergic rhinitis patients, for example, noted the study authors. Consequently, allergic diseases may be suitable targets for chronotherapy; various medications have improved efficacy when administered in the evening, including the antihistamine mequitazine.

Immunoglobulin E/mast cell-mediated allergic reactions exhibit circadian variations. Recent studies have shown that mast cells possess a functional molecular clock, and genes expressed exclusively or predominantly in mast cells exhibit circadian oscillations.

“These findings provide novel insight into the pathophysiology of allergic diseases,” concluded the researchers.


  1. Nakao A et al. Allergy. 2015; doi:10.1111/all.12596

This article originally appeared on MPR