Evaluation of Oxidant-Antioxidant Balance in Children with Atopic Dermatitis: A Case-Control Study.

Abstract

Increased reactive oxygen species (ROS) and oxidative stress (OS) has been reported in many allergic and inflammatory skin diseases, including urticaria, psoriasis, and atopic dermatitis (AD). Melatonin is a hormone secreted from the pineal gland and is a potent antioxidant. The aim of the study was to measure serum antioxidant melatonin, oxidants of nitric oxide (NO), and malondialdehyde levels to calculate the serum oxidant-antioxidant balance based on the NO/melatonin and malondialdehyde/melatonin ratios and to determine the correlation with the disease severity in children with AD. Seventy-three children with AD and 67 healthy controls were included in the study. The clinical diagnosis of AD was based on the diagnostic criteria of Hanifin-Rajka. The severity of AD was evaluated by the scoring AD (SCORAD) index, and atopy was determined by skin prick tests (SPTs) with commercial extracts. The OS-related parameters of serum melatonin, NO, malondialdehyde, and the NO/melatonin and malondialdehyde/melatonin ratios were calculated and compared with the results of healthy controls. Serum melatonin levels were higher (p<0.0001) and serum NO levels and the NO/melatonin and malondialdehyde/melatonin ratios were lower in children with AD than in healthy controls (p=0.045, p<0.0001, p<0.0001, respectively). There was no difference between children with AD and healthy controls in terms of serum malondialdehyde levels (p=0.119). Serum melatonin levels were significantly lower in severe AD than in mild AD (p=0.012). However, in terms of serum melatonin levels, there was no difference between mild and moderate AD (p=0.742) and moderate to severe AD (p=0.301). There was no significant difference in serum NO and malondialdehyde levels and NO/melatonin and malondialdehyde/melatonin ratios among children with mild, moderate, and severe AD (p>0.05). A negative correlation was found between serum melatonin levels and the SCORAD index (r=-0.252, p=0.031), and a positive correlation was found between NO/melatonin and malondialdehyde/melatonin ratios (r=0.511, p<0.0001). There was no statistically significant relationship between age (≤24 or >24months), disease duration (≤6 or >6months), and sex for the OS-related parameters (p>0.05). The serum oxidant-antioxidant balance was impaired in children with AD. Serum melatonin levels were higher in children with AD; however, this was negatively correlated with disease severity. Serum NO levels and NO/melatonin and malondialdehyde/melatonin ratios were lower in children with AD than in healthy controls. Melatonin might be used as a promising antioxidant to evaluate disease severity in children with AD. Thus, further studies are needed to clarify the role of melatonin in AD pathogenesis.