Interaction of sleep disturbance and nocturnal scratch in atopic dermatitis patients.

Introduction/Background Itch, scratch and poor sleep are often cited as key symptoms of Atopic Dermatitis (AD). Although approximately 10-41% of children and 7-48% of adults in the general population experience sleep disturbances, this figure climbs to 47-80% in children with AD and 33-90% in adults with AD (Bawany et al., 2021). While great effort has been done to characterize and validate nocturnal scratch and sleep, the relationship between the two remains poorly characterized. Objectives: We hypothesize that nocturnal scratch is the reason for the sleep disturbances in patients with AD. Literature suggests that these symptoms are linked, albeit not necessarily causal. Here we investigate the interaction between nocturnal scratch events and sleep disturbances in study participants with AD compared to a healthy cohort. Methods: Patients with AD (n=185) and without AD (n=40) aged between 2 to 75 years were recruited across three different studies. Study participants spent the night in a qualified sleep lab while being under observation with thermal videography and polysomnography (PSG). The thermal videography was annotated for both scratch and non-scratch movements by two trained annotators independently with any conflicts being resolved by an arbitrator. The PSG was scored by a credentialed technologist in 30-s epochs per revised American Academy of Sleep Medicine scoring guidelines. The study participants also wore a wrist-worn accelerometer on both the left and right wrists. Results: It was noted that sleep disturbances were associated with the observed scratch events, and that the temporal relationship between sleep disturbance and scratching seemed to differ between the AD and healthy cohorts. Surprisingly, however, it was also noted that within a few study participants with AD, scratch events occurred while the patient was in stable REM sleep, most often in the children with AD. Further investigation will provide additional information as to whether this was an artifact or in fact a true observation. We also present an overview of sleep, as well as nocturnal scratch and non-scratch movements in the AD and healthy cohorts, noting specifically how the behaviors differ between the groups, and over the course of the sleep opportunity, across sleep stages and sleep cycles, as well as their relationships to sleep disturbances. Conclusions: Nocturnal scratching is often associated with sleep disturbances in AD; however, the causality is not always clear. Moreover, in some cases scratching was observed during stable REM sleep in AD, an observation that requires further investigation. [ABSTRACT FROM AUTHOR]