Why does friction on the skin over a long period of time cause it to darken?

Question

I guess this is one of those human conditions that most of us hate and would like to know why it happens and how to prevent it!

In: 1

Answer 1

Do you mean like when you try to walk out new shoes and they leave dark red marks on your ankles from friction?

If so then because the material’s surface is irregular. It constantly scrapes the skin, creating lots of really small wounds and opening or crushing a lot of micro blood vessels present in our skin. The blood from them doesn’t have high enough pressure to exit through that scrape or sometimes it can’t do so cause the skin still remained in tact when the vessel broke, so it will get between the true skin and the external epidermis, leaving visible marks.