Infantile atopic dermatitis: Serum vitamin D, zinc and TARC levels and their relationship with disease phenotype and severity.

Background: Several markers that influence the clinical course of atopic dermatitis (AD) have been investigated so far. Thymus and activation regulated chemokine (TARC) - a Th2-related cytokine - increase in various atopic diseases. It has been shown that vitamin D affects Treg cells and immune responses. Zinc as an essential trace element for cell-cell interactions, cellular differentiation, and proliferation. However, the effect of these markers on infantile AD and disease severity are mostly unknown.
Objective: The aim of this study was to investigate the relationship between TARC, vitamin D, zinc levels, and the disease severity in infants with AD.
Method: AD patients (n = 160) with age and sex that matched healthy controls (n = 79) were included in the study. The diagnosis of AD was made based on the Hanifin-Rajka criteria. The objective SCORAD index was used for the assessment of disease severity.
Results: A total of 160 patients (male 71.9%) with AD were included in the study. The median age of onset of symptoms was 2 (1.0-3.5) months. The lesions initially started on face 76.9%, neck 6.9%, extremities 7.5%, and body 8.8%. Nearly 40% of the patients were found to be atopic. Food allergy was found in 39.4%. The median of objective SCORAD index was 27.5 (17.5-40) in the study group. The TARC levels of AD patients were higher than control group [1803 pg/ml (1006- 3123) vs 709 pg/ml (504-1147), p < 0.001] There was a significant correlation between objective SCORAD scores and TARC values in subjects with AD (r = 0.363, p < 0.001). As the severity of AD increased, vitamin D levels decreased (p for trend 0.015) and TARC values increased (p for trend < 0.001). Serum zinc levels did not change with the severity of the disease. The presence of atopy did not have an influence on serum TARC, zinc, and vitamin D levels.
Conclusion: In infants with AD, disease severity is positively related with TARC levels; and inversely proportional to vitamin D levels. TARC levels differ between patients and healthy controls. The presence of atopy has not been shown to affect these markers. © 2021 Codon Publications. Published by Codon Publications.
Competing Interests: The authors declare no conflict of interest. Hacettepe University Scientific Research Projects Coordination Unit provided financial support to this study and TARC kit was received with this financial support.