Allergies?

Ben has an appointment today with his new allergist. 

A few weeks ago, after eating at Steak n Shake, we noticed his face and lips were swollen.  This is the third time it has happened.  It happens sporadically, and we cannot figure out what causes it.  His pediatrician is concerned that it could be an allergic reaction and he gave us an epi-pen just in case it happens again and he has difficulty breathing.

Actually, the last time it happened was November 28, 2009, when he was first diagnosed with MD.  I took him to the emergency room and the doctor looked at his stomach and legs to see if he had a rash.  He did not.  However, she is the one who noticed his large calf muscles.  This is the day when all the other ER doctors came into our room and we were told that they strongly felt he had Muscular Dystrophy. 

After that episode, we had allergy testing done, along with the genetic testing for DMD.  The allergy testing came back negative.  It is all very confusing.  Now that the swelling has happened again, it is getting very concerning.  We have no idea what could be causing this.  He wasn't on any medication when it happened the first 2 times.  We are praying that they are able to figure this out so that we don't have more severe problems.