What is the best explanation for thin and dry skin in an 80-year-old woman?

The presence of thin and dry skin in an 80-year-old woman can be best attributed to the loss of subcutaneous fat and lower collagen content. As individuals age, there is a natural decline in the thickness of the skin layers, particularly the dermis, which is largely composed of collagen. Collagen is critical for maintaining skin elasticity and firmness. Alongside this, the reduction in subcutaneous fat contributes to the skin's ability to remain hydrated, as adipose tissue plays a role in moisture retention.

While genetic predisposition and damage from sun exposure can certainly influence skin characteristics, they are not the primary explanations for the changes seen in aging skin. Genetic factors may predispose someone to certain skin traits, but the overall aging process encompasses physiological changes that directly lead to thinness and dryness. Similarly, sun damage is often related to cumulative exposure over the years but does not solely account for the general thinning and dryness commonly seen in the elderly population.

The loss of sebaceous glands contributes to skin dryness, as these glands are responsible for producing sebum, which helps to maintain skin hydration. However, their decline is part of the broader picture of aging skin rather than the most encompassing explanation. Therefore, the most accurate explanation for the skin changes in an elderly