THE AGING INTEGUMENTARY SYSTEM
Jill Heitzman, PT, DPT, GCS, NCS, CWS, CEEAA, FACCWS
The skin is the largest organ of the body and the outward appearance of an individual that identifies one cosmetically, allowing identification and body image of a person. Over the lifespan, the skin becomes drier, less elastic, less perfused, and vulnerable to damage from pressure, friction, shear, moisture, and malnutrition. 1,2 These changes can impact the overall function of the skin. 3
The skin functions as a physical barrier to microorganisms to fight against infection, prevent excessive loss of fluids, provide sensation input, and is a storage for fat and water for metabolism and thermoregulation of the body. 1 Resident immune cells that participate in immune processes are present in the epidermis and dermis (Langerhans cells and dermal dendritic cells). The nerve endings present in the skin allow the ability to feel pain, pressure, heat, and cold. The skin functions as a thermoregulatory of body temperature through vasoconstriction, vasodilation, and sweating, allowing excretion of waste products, electrolytes, and water. Synthesis of vitamin D in skin exposed to sunlight activates metabolism of calcium and phosphates, which are important to bone formation and hormonal production and synthesis. A disruption in the skin, either directly or indirectly, as a result of underlying disease process, reaction to that process or medication, can alter the overall health of the individual. Underlying processes can also affect the healing phases of the integumentary system: inflammation, proliferation, and remodeling, including wound bed granulation, collagen formation, remodeling of the extracellular matrix, and reepithelialization. 4,5
There are many factors that impact the skin and ultimately wound healing, both intrinsic (emerge from internal physiological abnormalities) and extrinsic (external to the body). 6 Intrinsic factors include genetics and the aging process. However, advanced age alone does not impact wound healing. The independent aging factors typically do not cross over threshold of wound healing, but can be the basis for the changes that can occur with stressors. The extrinsic factors along with the presence of risk factors are what impairs the integumentary repair system in the aging adult. 7 Extrinsic factors include ultraviolet exposure, environment, and lifestyle that includes smoking, nutrition choices, and alcohol. Risk factors that add to the aging skin issues include medications, obesity, comorbidities, decreased mobility, decreased mental status, and incontinence. 8 Once a wound occurs, the healing process is affected by all these factors plus added factors of external pressure and bacterial burden. 2
Biological changes that occur with aging include a decrease in the vascularity, dermal tissue thickness, number and size of sweat glands and hair follicles, epidermal cell turnover rate, collagen density and elastin fibers, and number of Langerhans cells and melanocytes. These changes make the epidermis less effective in protecting the body from infection and dehydration. The changes in the basal cells lead to a ...