Sunburn is a visible sign of injury to the skin caused by overexposure to ultraviolet (UV) radiation. The immediate reaction, characterized by redness and heat, is the body’s inflammatory response to this damage. Skin peeling, which often follows a few days later, is a natural and necessary part of the healing process, shedding the damaged outer layer to reveal healthier cells beneath.
The Cellular Damage Caused by Sun Exposure
Ultraviolet B (UVB) radiation is the primary culprit in causing sunburn, as it penetrates the epidermis. Once inside the cells, the high-energy UVB rays directly attack the genetic material within the keratinocytes, the main cell type in the epidermis. This attack can break or distort the chemical bonds in the cell’s DNA, creating mutations that the cell cannot easily repair.
The immediate redness, swelling, and pain of sunburn are signs of an acute inflammatory response triggered by this cellular trauma. Damaged cells release chemical signals, such as tumor necrosis factor-alpha (TNF-alpha), which increase blood flow to the area. This rush of blood brings immune cells to the site to begin clearing debris and initiating the repair process.
The body recognizes that the DNA damage in these skin cells is too extensive to fix safely. If these damaged cells were allowed to survive and reproduce, they could potentially lead to the formation of skin cancer years later. Therefore, the inflammatory cascade acts as a signal for the body to deal with the irreparably harmed cells.
Apoptosis: The Biological Reason for Skin Peeling
Peeling is the physical result of apoptosis, a biological self-defense mechanism known as programmed cell death. This process forces severely damaged keratinocytes to commit cellular “suicide” before they can become cancerous. Keratinocytes undergoing this process are sometimes referred to as “sunburn cells.”
Once the immune system initiates apoptosis, the damaged cells begin to shrink and detach from the healthy tissue underneath. This is a quiet and controlled form of cell death, designed to prevent a large, messy inflammatory reaction. The damaged outer layer of the epidermis separates from the newly forming, healthy skin layer below.
The entire process, from initial sun exposure to the completion of peeling, can take approximately one week. Peeling typically begins two to three days after the burn. This shedding is a necessary protective action, ensuring that cells with potentially harmful mutations are eliminated.
Supporting the Skin During the Healing Process
Once peeling has begun, the focus shifts to supporting the new, sensitive skin underneath. The newly exposed layer is fragile, making gentle care important for proper recovery. The most helpful approach is to provide deep hydration, both internally and externally, to aid recovery.
Drinking extra water helps to rehydrate the skin from the inside, counteracting the dehydration caused by the sunburn. Applying a gentle, hydrating moisturizer or pure aloe vera gel externally helps to soothe the area and lock in moisture. For the first few days, it is best to avoid oil-based lotions, as these can trap heat and worsen the initial burn.
It is important to resist the strong temptation to pick at or pull off the peeling skin. Doing so can remove skin that is not ready to shed, potentially exposing the raw, underlying tissue to infection and prolonging the healing time. The skin should be allowed to slough off naturally, aided by cool, gentle baths or showers.