what does bum allergy ring look like?

[LBMarie9]

I have never noticed this on my kids--however we just moved--just had a baby and have been eating my freezer meals for a couple weeks (more lax on ingredients?! i dunno) and today my son has a horrible red ring around his bum- there is a darker line that lines the redness. HOWEVER he also has red pimply bumps all over his bum.  reaction? or just staph? he has had staph "type" "folliculitis" bumps on the back of his one knee--we tried anti-biotic ointment and it didn't work. he doesn't have any oral anti-biotics that he isn't allegic too or is unresponsive (and I wouldn't want to give oral for a skin infection anyways)--and those bumps never went away (always there--sometimes better and worse on the back of his knee)---SOOO could this be spread from that? or reaction? is a red ring around bum even characteristic of staph? any other things that it could be besides a reaction that would need to be treated? thanks!

[Brees_Mama]

These might help:

http://www.mothering.com/community/forum/thread/718945/does-an-an-allergy-ring-on-the-bottom-always-equal-a-food-allergy

http://www.mothering.com/community/forum/thread/1003366/allergy-ring-what-does-it-look-like

http://www.justmommies.com/boards/lofiversion/index.php/t569945.html