Sunburn is itchy because the damaged skin triggers an inflammatory response, leading to the release of itch-inducing substances like histamine.
Here's a breakdown of the process:
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Skin Damage: When you get a sunburn, the sun's ultraviolet (UV) radiation damages the outer layer of your skin (epidermis). This damage injures or kills skin cells.
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Inflammation: The body responds to this damage with inflammation. This inflammation is a complex process involving immune cells rushing to the affected area.
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Neurogenic Inflammation: A specific type of inflammation called neurogenic inflammation can occur. This involves the release of neuropeptides, signaling molecules, that directly stimulate nerve endings in the skin.
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Histamine Release: As part of the inflammatory response, some immune cells release histamine. Histamine is a chemical that causes blood vessels to dilate and become more permeable. It also binds to receptors on nerve endings, causing the sensation of itch.
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Nerve Stimulation: The combination of neuropeptides from neurogenic inflammation and histamine directly stimulates nerve endings in the skin, sending signals to the brain that are interpreted as itch.
In summary, sunburn itchiness results from a cascade of events triggered by UV radiation damage, leading to inflammation and the release of itch-inducing substances that stimulate nerve endings in the skin.
