orange/brownish discoloration on bottom of feet
help! yesterday afternoon, my 3 year old son woke up from his nap with orange/brownish splotches on the bottom of both feet and one oval patch of a lighter stain on his calf. I tried to wash it off, but it wouldn't come off. Today, myself and my other son (9 years old) have the same discoloration pattern on the bottom of our feet. my daughter (5) does not.
I'm perplexed as to what is causing this. we all walk on the same floors, eat the same food, etc. It's not red and itchy like a rash -- just a random set of splotches on just the bottom of our feet (with the exception of the one spot on my son's calf.
i've been a parent for 22 years and have never come across something like this. searching online has been fruitless -- there's nothing even remotely close to this posted anywhere.
any suggestions or help would be appreciated.