I have a sort of rash on my arms...

Hi there, I know this isn't really connected to the "Women's" part of this club, since my father has this too, but I thought this was the best place to ask.

For ages I've had little red spots on both my upper and forearms. One of my aunties told me it was a lack of fisch oil, another told me it was a hormone imbalance and another told me I wasn't getting enough iron. They are really annoying (even though they don't itch oder irritate oder anything) but they stop me wearing vest tops oder anything that shows my arms really. Do Du know what it is?