Until recently, skin aging was largely equated with photoaging, and the abnormalities in photoaging have been largely localized to the dermis. Recent studies1 have shown that chronological aging alone produces important abnormalities in epidermal function that are revealed only when the skin barrier is perturbed. These alterations include a profound abnormality in stratum corneum integrity (cohesiveness) and permeability barrier homeostasis, reflected by a delay in barrier recovery after barrier disruption.1 We explored whether photoaging imposes an additional functional deficit on chronologically aged (CA) skin (Table).2,3
Assessment of Barrier Function Under Basal Conditions.
Prior studies1 from our and other laboratories have shown that barrier function under basal conditions in nonphotoaged, CA skin is slightly lower than normal. Furthermore, in a pilot study in young people (20-30 years old), we confirmed the finding of others4,5 that there is no significant difference in volar vs dorsal forearm transepidermal
Reed JT, Elias PM, Ghadially R. Integrity and Permeability Barrier Function of Photoaged Human Epidermis. Arch Dermatol. 1997;133(3):395-396. doi:10.1001/archderm.1997.03890390139031