So there's this thing called polymorphic light eruption (which is a stupid convoluted science word for sunburn):
"The cause of polymorphic light eruption is unknown. It is postulated that there is a delayed hypersensitivity reaction to an endogenous antigen expressed after exposure to sunlight or artificial sources of ultraviolet (UV) radiation."
Hypersensitivity means allergic reaction. UV radiation is murking your exposed skin cells because it causes such severe DNA damage that the cells commit suicide in a process called 'apoptosis.' The body's immune system is freaking out because it's seeing a bunch of stuff all of a sudden, that has floated out of your dead skin cells, that it isn't supposed to see. It releases a ton of chemicals that make you feel nauseous, crappy, and sore, and which normally are key parts of fighting infection as part of the inflammation reaction.
Oakley AM, Ramsey ML. Polymorphic Light Eruption. [Updated 2020 Aug 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430886/
This results in:
> "Release of inflammatory markers such as prostaglandins, reactive oxygen species, and bradykinin."
> "This leads to vasodilation, edema, and pain which translates into the classically red, painful skin seen in a sunburn."
> "Additionally, skin exposure to UVB causes an increase in chemokines such as CXCL5 and activates peripheral nociceptors, which results in over-activation of the pain receptors of the skin."
Guerra KC, Urban K, Crane JS. Sunburn. [Updated 2020 Aug 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534837/
That allergic reaction is in addition to the common damage to the DNA of the skin cells caused by the UV radiation, that may occur before you get any of that pain and swelling. This is scary because if the cells are dead, ok you get a sunburn, but that's because they're dead. If the DNA is damaged and the cells don't die, you can lose genes like cell cycle checkpoint inhibitors and tumor suppressors. And BAM, melanoma which winds up killing somewhere in the ballpark of 9,000 people in the U.S. each year, as well as squamous cell carcinoma which kills like another 15,000.
"The cause of polymorphic light eruption is unknown. It is postulated that there is a delayed hypersensitivity reaction to an endogenous antigen expressed after exposure to sunlight or artificial sources of ultraviolet (UV) radiation."
Hypersensitivity means allergic reaction. UV radiation is murking your exposed skin cells because it causes such severe DNA damage that the cells commit suicide in a process called 'apoptosis.' The body's immune system is freaking out because it's seeing a bunch of stuff all of a sudden, that has floated out of your dead skin cells, that it isn't supposed to see. It releases a ton of chemicals that make you feel nauseous, crappy, and sore, and which normally are key parts of fighting infection as part of the inflammation reaction.
Oakley AM, Ramsey ML. Polymorphic Light Eruption. [Updated 2020 Aug 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430886/
This results in:
> "Release of inflammatory markers such as prostaglandins, reactive oxygen species, and bradykinin."
> "This leads to vasodilation, edema, and pain which translates into the classically red, painful skin seen in a sunburn."
> "Additionally, skin exposure to UVB causes an increase in chemokines such as CXCL5 and activates peripheral nociceptors, which results in over-activation of the pain receptors of the skin."
Guerra KC, Urban K, Crane JS. Sunburn. [Updated 2020 Aug 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534837/
That allergic reaction is in addition to the common damage to the DNA of the skin cells caused by the UV radiation, that may occur before you get any of that pain and swelling. This is scary because if the cells are dead, ok you get a sunburn, but that's because they're dead. If the DNA is damaged and the cells don't die, you can lose genes like cell cycle checkpoint inhibitors and tumor suppressors. And BAM, melanoma which winds up killing somewhere in the ballpark of 9,000 people in the U.S. each year, as well as squamous cell carcinoma which kills like another 15,000.
https://www.cdc.gov/cancer/uscs/about/data-briefs/no9-melano...
https://www.skincancer.org/skin-cancer-information/skin-canc....