Background: Little is known on sleep quality of children with atopic dermatitis (AD) during flares and how treatment impacts their sleep. The purpose of this study is to evaluate variations in sleep quality of children with AD during flares and its response to intensified treatment. Material and Methods: Prospective case-crossover study in 10 children with moderate-severe AD. At baseline, AD severity was assessed using SCORAD and patients were prescribed intensified AD therapy. All subjects were monitored by actigraphy during 14 days and returned for SCORAD assessment. Results: Subjects' age was 5.6 +/- 5.3 years; 50% were female. Sleep duration was decreased in all subjects and awakenings were increased in 90%. Parental perception of sleep significantly differed from actigraphy results: parents estimated less sleep duration and less awakenings. Nocturnal sleep efficiency at baseline was reduced in 50%. After intensified treatment, median SCORAD decreased from 58.5 to 31.3 (p=0.005), with significant improvement in sleep loss and pruritus visual analogue scales. Despite improvement of SCORAD and parental perception of sleep loss and pruritus, objective sleep duration and efficiency measured by actigraphy did not vary significantly after intensified treatment. Change in SCORAD, sleep loss and pruritus scales did not correlate significantly with change in sleep duration, efficiency or other actigraphic sleep quality measurements. Conclusions: Children with moderate-severe AD have sleep quality abnormalities, with decreased sleep duration, low sleep efficiency and increased awakenings. Improvement in AD severity upon intensified AD treatment was associated with improved parental perception of sleep loss, but not of objective sleep quality assessed by actigraphy.