Melatonin and sleep disorders in patients with severe atopic dermatitis

Introduction
Many atopic dermatitis (AD) patients suffer from insomnia. Out of numerous factors associated with sleep disorders, melatonin seems to play a significant role.

Aim
To assess the relation between melatonin concentration and sleep disorders in adult patients with severe and very severe AD.

Material and methods
The study included 36 adult patients with severe and very severe AD and 20 healthy Caucasian volunteers. The severity of skin lesions was assessed by the EASI scale. Skin itch was evaluated by a visual-analogue scale (VAS), and sleep disorders were assessed by the Polish version of the Athens Insomnia Scale (AIS). Serum melatonin concentration of patients and controls was determined by ELISA.

Results
Melatonin concentration in patients with very severe AD was significantly (p < 0.001) lower than in patients with severe AD, however, melatonin concentration in the group of AD patients did not differ significantly (p = 0.33) from that observed in the control group. There was a significant negative correlation between the concentration of melatonin in the study group and the severity of itching (R = –0.54, p < 0.001). The intensity of sleep disorders was significantly higher (p < 0.001) in patients with a very severe form of AD compared to patients with severe AD. Moreover, there was a significant negative correlation between melatonin concentration and sleep disorders (R = –0.67, p < 0.001).

Conclusions
Our results clearly showed that sleep disturbances are more expressed in very severe AD patients compared to subjects suffering from severe disease. We also suggest that melatonin serum concentration could play a role in the pathogenesis of sleep disturbances in AD patients.