Reoccuring hive-like bump, exact same spot for months, what could it be?

[allie997]

Since september of last year I've gotten a: reoccuring, circular, red, itchy bump that keeps appearing in the exact same spot. This happens every 2-3 weeks. It starts off like a raised mosquito bite, red and kind of small, only to flatten out into a perfectly circular shape about 30-40 minutes later. The red circular shape lasts all day and by the next day it's less red. Since I've gotten this every 2-3 weeks now since september and it's now may, it's made the skin on that spot become a little darker.

I saw a dermatologist and she prescribed me a steroid cream and anti-histamines. The steroid cream hasn't helped, and I've yet to try the anti-histamines. She says she doesn't know exactly what it is.

This is so frustrating since there's very few sites that talk about the exact same issue. Does anyone have any idea what it could be?

Thank you.