Every year(usually in Summer) I get some kind of itchy red bumps on my chest and back. Sometimes my arms too. It's never spread anywhere else though. I don't know if your and my bumps are the same, but I've been gettin them from a while. Few years maybe. They may not be the same thing though. Since mine don't go past my upper body. And the red bumps I get are tiny.

I live in central TX and since I moved here I've noticed bumps too. The ones I'm thinking of in particular are three small bumps about 3mm in diameter and like a triangle toegether, the whole thing no bigger than 1/2 inch. We're currently battling a flea infestation but I don't seem to be getting marks from those - and I've only gotten these bumps rare/occasionally and maybe only in warmer months - will pay more attention.