Sleep disturbance in patients with lichen simplex chronicus and its relationship to nocturnal scratching: A case control study

Background: Lichen simplex chronicus (LSC) is a common pruritic disorder resulting from repeated rubbing and scratching. Nighttime pruritus is a common feature in LSC and may disrupt the sleep pattern. The aim of this study is to determine whether there are sleep abnormalities in patients with LSC. Patients and Methods: Fifteen patients with LSC and 15 age-, sex- and body mass index-matched control subjects were enrolled in the study. No participant had any other medical or psychiatric illness. All subjects were evaluated by overnight polysomnography, scratch electrodes, Epworth sleepiness scale and a general questionnaire for demographic data and sleep problems. Results: There were no significant differences in the groups for total sleep time, sleep efficiency, sleep latency, rapid eye movement (REM) latency, percentage of stage I non-REM sleep and REM sleep. The percentage of stage 2 non-REM sleep was higher (P < 0.05) and the percentage of slow wave sleep (stages 3 and 4) was lower in the study group (P < 0.05) than in the controls. The patient group had a mean of 15.9 +/- 7.5 arousal index and 22.8 +/- 14.1 awakenings compared with 9.5 +/- 3.1 and 10.4 +/- 3.9, respectively, in the controls (P < 0.05, P < 0.01, respectively). Arousals of patients were mainly observed in non-REM sleep. The number of scratching bouts ranged from 6 to 20 per night. Scratching episodes were observed frequently during stage 2 non-REM sleep. Conclusion: Polysomnographic findings of patients with LSC demonstrated that sleep structure is disturbed by arousals and awakenings related to scratching bouts during sleep.