My mother has been suffering from an unknown skin condition since last 8-9 years (See the picture). Anyone having any clue, please help.

[devyani2302]

It is non-contagious, symptoms include severe itching which aggravates on exposure to sun/heat. Her skin has become dark, pigmented, thickened, rough and dry. It even bleeds at times due to scratching when it itches. Exposed parts are mostly affected like arms, face, neck and back. Hands and feet are unaffected.