Red Rash On Legs Red Rash On My Legs That I Get In Any Heat?

Red rash on my legs that I get in any heat? - red rash on legs

I'm always the heat, you see a strange red rash on his legs. I do not believe anything, and only appears in the heat (shower, exterior, etc) I know not start them until a year ago. If anyone knows what it is or how to get rid of him, please help me.

Thank you! :]