The evaluation of melatonin levels in chronic spontaneous urticaria: A case control study

Background: Although sleep disturbance is known to be common in patients with chronic spontaneous urticaria (CSU), sleep hormone levels in the blood have never before been studied in CSU. Objective: In this study, we aimed to evaluate the serum melatonin levels in patients with CSU. Methods: For the patient group, 80 patients with recently diagnosed CSU, and, for the control group, 75 healthy controls (HC) were included. The study participants' melatonin levels were measured by using the enzyme-linked immunosorbent assay method. CSU disease activity was evaluated by using the urticaria activity score-7 (UAS-7), and the quality of life was assessed with the chronic urticaria quality of life questionnaire (CU-Q2oL). The patients with concomitant diseases likely to affect the melatonin levels or those using related medications were excluded from the study. Results: The patient group consisted of 53 female subjects (67%); the median (interquartile range) age was 34 years (27-43 years). The levels of melatonin were lower in the patients with CSU when compared with the HCs (p < 0.03). The melatonin levels had no significant relationship between UAS-7 and the total scores in CU-Q2oL (p > 0.05). However, a significant negative correlation in the melatonin levels was observed with questions 7 (overall sleep assessment) and 11 (difficulty in falling into sleep) in the CU-Q2oL (r = -0.55 [p < 0.001] and r = -0.62 [p < 0.001], respectively). Conclusion: The presence of low melatonin levels in the patients with CSU suggests that melatonin has a key regulatory role in the CSU development in addition to the deterioration in sleep quality. A new treatment strategy to increase the melatonin levels in CSU may be pursued in further studies to confirm our findings.