I'm currently hitchhiking in South East Asia where it's of course always hot. I'm getting a rash around my ankles that I've had in the past but never looked into.
(The same rash, but on a different trip, in Korea, about 5 years later.
In Australia I guess we would call something like this "heat rash", though I was never prone to such things when I was younger so I'm not that familiar with what such rashes look like. Doing some Googling it seems to be known as "golfer's vasculitis".
It doesn't hurt or itch or sting. I know it's not caused by poison ivy or allergies. It just looks ugly plus I wonder if it could be doing harm that I don't know about.
I thought it might be to do with type of socks or socks being too tight. But those are just guesses. Is there something that can be done to prevent getting this rash?