Metal hypersensitivity, a disorder of the immune system, typically manifests as contact hypersensitivity to metals during daily contact. The molecular mechanism whereby metals enter the body and cause allergic disorders remains elusive. It is thought that eluted metal ions are captured by dendritic cells (DCs) and transferred to the draining lymph nodes to activate T cells. Here, for the first time, we used a metal indicator Newport Green to locate the most common allergenic metal, nickel (Ni) ions, captured by DCs and transferred to lymph nodes. Capturing Ni ions did not affect the activity of DCs. Ni ions entered DCs and showed positive staining in keratinocytes. A time varied quantitative analysis demonstrated that at 1 h, a small amount of Ni ions was observed in the epidermal sheet. After 6 h, the number of Ni ions that entered the epidermal sheet reached a peak and remained constant for a few days and were gradually emitted 48 h later. In the cervical lymph nodes of mice, accumulation of Ni ions reached a peak within 24 h and then gradually decreased. The findings of this study will contribute to the development of effective diagnoses and treatment methods for patients allergic to Ni.