A Answers (2)
Mehmet Oz, MD, Cardiology, answeredAs we age, our skin cells slow down, meaning our skin doesn't rejuvenate itself as quickly or as much as it does when we're younger, and the skin starts to thin. At the same time, the fat cells below your skin start to degrade, causing skin to hang more freely. Other thin skin culprits are overexposure to the sun, which can affect your skin's elasticity, medical disorders or conditions, and certain medications such as corticosteroids.
Skin thickness can vary depending on a person's age, the area of the body in question, the amount of sun exposure a person has experienced over time, and a person's health.
About 90% of the skin's thickness is from the dermal layer of the skin, and much of the variation in skin thickness there is due to variations in collagen and elastin levels. Collagen and elastin break down with age. A gradual decrease in subcutaneous fat in the hypodermal layer of the skin also occurs with age, further decreasing skin thickness. Variations in thickness of these layers have the most dramatic effect on skin appearance.
Variations in thickness are common in the corneal layer of the epidermis, too, which is the thin, outermost sublayer of the epidermis. The corneal layer is thicker on areas of the body that need more protection or more grip, such as the palms of the hands and soles of the feet. Sun exposure influences the thickness of the corneal layer, as well. Someone who spends little time in the sun will have a thin corneal layer, which provides less protection from the sun and allows the sun's rays to penetrate more deeply.
Some medical conditions, such as diabetes and thyroid disorders, can affect skin thickness, too.