Asthma, atopic dermatitis, and allergic rhinitis display a marked circadian variation with the maximum of disease activity during the night. Due to the consecutive disruption of sleep architecture, affected children often suffer from daytime sleepiness and have reduced quality of life. Currently there is a diagnostic gap in detecting nocturnal asthma and allergy symptoms, leading to a significant underestimation of the frequency. Caring for children with asthma, atopic dermatitis, and/or rhinitis should include standardized detection of nocturnal symptoms and a regular assessment of sleep quality and potential daytime sleepiness. Vice versa, in the differential diagnostic of a child with enhanced daytime sleepiness, the very frequent atopic diseases should be routinely considered. As asthma and obstructive sleep apnea syndrome often occur together, the presence of one of these two diseases should prompt the systematic search for the other one. [ABSTRACT FROM AUTHOR]