The amounts and distributions of chemical elements in skin are important to maintain homeostasis. For example, gradients of Ca, K, and Mg have been well investigated and play roles in keratinocyte differentiation and water-impermeable barrier homeostasis. [1][2][3][4] These gradients are disrupted after barrier disruption or in patients with diseases associated with barrier dysfunction, such as psoriasis or atopic dermatitis. [4][5][6] Furthermore, Zn, Cu, Fe, and Mn in keratinocytes are involved in wound healing, 7-10 while Se has a role in protection against ultraviolet radiation (UV). 11 Several reports have suggested that Zn and Sr might be associated cutaneous pruritus. 12-14 Therefore, observation of the amounts and distributions of chemical elements in the skin can give us important information about skin pathology. So far, X-ray microanalysis methods, such as electron-probe X-ray microanalysis (XRMA) and particle-induced X-ray emission (PIXE), and fluorescence microscopy using chemical indicators have been used for this purpose. [4][5][6]15,16 However, XRMA