Odd skin rash on legs, looks like red spray paint blotches?

Has anyone ever heard or seen this? My bro-in-law has them on his legs.|||I had something like this. Are you tanning? I got them from tanning and when I researched it online, it said that taking birth control increases your chance of it happening. Its nothing to worry about. Just if you are tanning, decrease your time in the bed and the frequency. It goes away.|||He needs to go to the doctor He may have cellulitis|||The mottled skin is from repeated exposure to heat. I have this and I left you the link. Most doctors do not know this condition. Erythema means red. Atrophy means skin thinness. Putting steroid creams on it will make it worse.