Allergic to Certain brands of beer? Mostly Domestic not imported

I am having a real difficult time identifying what it is in certain beers that I am allergic to. I can drink most all Mexican beers such as Corona, Tecate, Dos-X, SOL, Negra Modelo etc, but most domestic brands such as Bud, Miller, Coors, and most all micro-brews give me nearly instant asthma-like symptoms. I can Dring Blue-Moon by Coors (my go-to-staple) but would love to be able to identify the component so I can try and enjoy other brands. I have read that some beers contain preservatives such as sulfites , but it's nearly impossible to find out who does. They all seem to hide the ingredients when it comes to that touchy subject. Anyone else have a similar allergy? Tweet