Age-related changes of stratum corneum functions of skin on the trunk and the limbs

Despite our understanding that the care of back and buttock skin is important for elderly nursing patients, the stratum corneum (SC) functions of the skin on the trunk of elderly patients have not been well investigated.

Overall, 41 elderly subjects (average age: 75.9 years, 20 male and 21 female) and 20 middle-aged subjects (average age: 41.3 years, 10 male and 10 female) residing in Tokyo were recruited. Hydration of the SC, transepidermal water loss (TEWL), skin surface pH, total bacteria and inflammatory cytokines in the SC of skin on the buttocks, back, lower leg and inner forearm were measured.

The hydration of the SC decreased only on the lower leg with age. TEWL showed no change with age at any site. The pH was significantly higher in elderly skin than in middle-aged skin at all sites. The number of total bacteria on the forearm and back increased with age. The ratio of interleukin-1α (IL-1α) and IL-1α receptor antagonist was only higher on the middle-aged forearm compared to the elderly. No remarkable gender difference was found in these parameters without pH values. We clarified that most of the SC functional parameters change with age on both the trunk and the limbs in a similar manner, suggesting that the limbs are acceptable sites to estimate the SC functions of the trunk of elderly patients. Our study may be useful as basic data for future work to maintain the SC function of elderly patients.