[Results] From 10 weeks after the start of feeding, special diet-fed B6 mice exhibited decreased skin conductance and increased TEWL, indicating a decreased skin hydration and impaired skin barrier function, respectively. Histological examination showed epidermal hyperplasia and an increase in dermal mast cells in special diet-fed mice, as in AD patients. Special diet-fed mice showed an increase in spontaneous scratching as well as alloknesis. Furthermore, certain hypnotic drugs, such as ethanol and phenobarbital, markedly enhanced scratching in special diet-fed mice, but not normal ones. Although phenotypic differences among B6 substrains have been reported especially with respect to pain sensitivity, there was no significant difference in itch-associated scratching responses between substrains (B6N and B6J) and between male and female mice.