Nocturnal Scratching and Quality of Sleep in Children with Atopic Dermatitis

Itching due to atopic dermatitis causes sleep disorders in children, but its pathology is unknown. The aim of this study is to investigate nocturnal scratching as an indirect index of itching during sleep and its relationship with depth of sleep in children with atopic dermatitis. Nocturnal scratching was measured in a total of 20 children with atopic dermatitis, using a smartwatch installed with the application Itch Tracker. Depth of sleep was analysed using polysomnography. The severity of atopic dermatitis was scored using Eczema Area and Severity Index (EASI) and Patient-Oriented Eczema Measure (POEM). The number and time of nocturnal scratching measured by Itch Tracker had a significantly positive correlation with EASI scores, whereas POEM scores were not correlated with EASI scores. Mean sleep efficiency was 90.0% and scratching episodes (n = 67) started mainly during the awake stage or light sleep stages. In the scratching episodes that started during sleep stages (n = 34), the sleep stage changed to a lighter one or to the awake stage in 35.5% of episodes. Itch Tracker is applicable to measure nocturnal scratching in children. Nocturnal scratching can deteriorate quality of sleep by changing the sleep stage to a lighter one or to the awake stage. SIGNIFICANCE This is the first study to simultaneously use Itch Tracker, a recently-developed app for measurement of nocturnal scratching, and polysomnography to assess nocturnal scratching and its influence on quality of sleep in children with atopic dermatitis. The results show a positive correlation between severity of atopic dermatitis and scratching, as well as indicating deterioration of quality of sleep during scratching in these children, adding to the evidence regarding quality of sleep impaired by itch in children with atopic dermatitis.