Irritability of the skin barrier: A comparison of chronologically aged and photo-aged skin in elderly and young adults

PurposeThe epidermal barrier resides in the stratum corneum (SC). Compared to young adults baseline barrier function of aged skin is comparable. Stress to the aged barrier results in decreased rates of repair. Barrier irritability of young vs. old, chronologically aged vs. photo-aged skin has not been examined in direct comparison.Patients and methodsGeriatric patients (mean age 81 ± 7 SD; n = 104) underwent a dermatological examination. The irritability of young (24 ± 3; n = 21) vs. old (82 ± 5; n = 21), chronologically aged (ventral side of the upper arm) vs. photo-aged (dorsal aspect of the lower arm) skin was assessed, including transepidermal water loss (TEWL), SC hydration before and after 10 minutes irritation with 0.5 N NaOH under occlusion.ResultsClinical examination of aged subjects revealed a correlation between excessive dry skin and photo-aged, but not chronologically aged skin (P < 0.05). Compared to young adults’ SC hydration was lower in photo-aged skin sites of the elderly (P < 0.001). Basal TEWL was comparable in young, chronologic and photo-aged skin. Only photo-aged skin of old subjects revealed increased irritability to the alkaline irritant compared to chronologic aged and young skin (P < 0.001).ConclusionSkin dryness and irritability in the elderly is enhanced only in photo-aged skin.