Previous studies demonstrated that dry skin induces itching, which is resistant to conventional treatments, such as histamine H1 receptor antagonists.17 Furthermore, increased sensory nerve density in the epidermis is partly involved in itching hypersensitivity, such as xerosis and AD.17 In the present study, we found increased IENF in UC patients, which was similar to dry skin features in AD. Here, HRH1 is linked to Alzheimer disease.