Why does our skin peel after a significant sunburn?
At first blush (yes, a pun of sorts) it seems obvious: Burn the skin and it’s damaged and falls away. But of course it’s not quite that simple. The top layer of the epidermis is dead tissue anyway and is continually wearing and flaking away. This is several layers away from the living tissue which one presumes is most affected by UV overexposure. So how does that translate into the topmost layer letting go en masse?
I would assume that it is the same as when you burn your finger. You get a bliter and the skin lifts, fills with fluid, and eventually comes off. A bad sunburn can cause extreme blisters. Maybe a more mild sunburn just causes microscopic blisters, and the skin falls away sooner. Just a thought. Don’t qute me on that.
I’m going to step out on a limb here…
The upper layers of skin are supported by lower layers. Yes, the very top layer is dead, but the layer just beneath it isn’t. Sunburning kills the layer just beneath the top layer, causing it to slough off prematurely. The top layer comes off because the layer just underneath anchoring it comes off.
This would also account for why the skin under sunburn peel is a little more tender than unpeeled skin - it’s reaching the surface a little sooner than it ordinarially would.