After I eat a meal with a modest amount of carbs (>25g or so) within an hour or two I get raised itchy bumps on my face. They typically swell up to the size of a dime.

Over the course of 8 hours or so shrink they down into small pimples with white heads. This occurs with ANY type of carb and isn't caused by any single type of food. For example, If I eat 1/4 of a 60g carb food v. the entire 60g I don't get the reaction. I've tested this with grains, high carb vegetables, fruits etc.

Has anyone dealt with a similar issue that can provide any insight?