ABSTRACT
Background@#Atopic dermatitis is a chronic, inflammatory disease affecting the skin including the scalp, nails, and lips. One of the main pathogenesis of atopic dermatitis is skin barrier impairment. Transepidermal water loss is a noninvasive measurement of water loss across the stratum corneum for assessing skin barrier function. @*Objective@#This study aimed to evaluate the skin barrier function of various skin sites including hairy skin, non-keratinized areas, and hard keratin in patients with atopic dermatitis. Furthermore, the relationship between the severity of atopic dermatitis and transepidermal water loss was investigated. @*Methods@#In total, 73 patients with atopic dermatitis and 65 age-matched healthy controls were included in this study. Transepidermal water loss was measured at 8 different skin sites including hairy skin (vertex, occiput), the cheek, non-keratinized area (lower lip), lateral side of the upper arm, flexor side of the forearm, extensor side of the forearm, and hard keratin (fingernail). The severity of atopic dermatitis was assessed using the eczema area and severity index. @*Results@#Transepidermal water loss was observed to be higher at all the measured sites including the scalp, nails, and lips of atopic dermatitis patients in comparison with that of the age-matched controls. Transepidermal water loss were correlated with the severity of atopic dermatitis in the cheek, lips, upper arm, and forearm. @*Conclusion@#Patients with atopic dermatitis have impaired skin barrier function, including in regions of hairy skin, non-keratinized areas, and hard keratin areas. Barrier dysfunction is associated with the severity of atopic dermatitis.