Association of oxidative stress and dynamic thiol‐disulphide homeostasis with atopic dermatitis severity and chronicity in children: a prospective study

Summary Background Oxidative stress ( OS ) has an important effect on the pathogenesis of atopic dermatitis ( AD ). Thiols are antioxidants that regulate intracellular redox metabolism and protect keratinocytes against OS damage in the stratum corneum. Aim To investigate dynamic thiol‐disulphide homeostasis ( dTDH ) as a novel OS parameter in children with AD , and its relationship with disease severity and chronicity. Methods Severity of AD was determined by using the instruments SCOR ing Atopic Dermatitis ( SCORAD ) and Eczema Area And Severity Index ( EASI ) upon enrolment in the study ( SCORAD 1 and EASI 1 ) and after 1 year ( SCORAD 2 and EASI 2 ). Native thiol, total thiol and disulphide levels were measured as novel OS parameters, and the ratios of disulphide/native thiol, disulphide/total thiol and native/total thiol were calculated as dTDH . Results In the AD group, the serum disulphide level and the ratios of disulphide/native thiol and disulphide/total thiol were significantly lower than in healthy controls ( P  = 0.01, P  < 0.01 and P  < 0.01, respectively). There was no significant association between OS parameters and disease severity ( P  > 0.05). SCORAD 2 and EASI 2 were positively correlated with disulphide/native thiol ratio ( r  = 0.29, P  < 0.03 and r  = 0.35, P  < 0.01, respectively), whereas they were negatively correlated with the native/total thiol ratio ( r  = −0.30, P  = 0.02 for both). Conclusions Both OS and impaired dTDH were found to be related to childhood AD . None of the OS parameters was associated with AD severity. dTDH is a possible diagnostic tool to predict AD chronicity.