Itching and Burning Legs While Exercising?

When my mother walks for a long time, like walking as a form of physical activity or exercise, for about 10 minuntes, her legs itch and burn and she has to stop right away to rub her legs in attempt to stop the itching and burning. The itching and burning occurs in her inner thighs but she does not know if they itch and burn internally or externally, so it may be both; she can't tell the difference since the feeling is very exstrusiating. What causes this and how can this issue be cured or fixed?

[gymdandee]

http://www.livestrong.com/article/424864-itchy-legs-during-walking-or-running/

[Victoria3719]

Thanks! :)