**3. Conclusions**

AD is a complex cutaneous disorder characterized by local and/or systemic immune reactions, and skin barrier dysfunction. Its clinical manifestations are affected by many factors, such as gene, environment, race, age etc. Further studies should be performed to findings of definitive biomarkers to assess the disease severity and evaluation of treatment effects. But the normal levels in infancy and age-specific analysis in AD of these markers have not been well determined, this should be taken into account when interpreting the results, especially in infant AD.
