Mystery Diagnosis

Last Thursday Dayton had a mystery diagnosis.  It was really weird.  The night before Dayton was fine.  No fever, no runny nose, no cough, no sore throat.  He went to school and he was fine.  No symptoms of any cold or cough.  By noon Dayton's school teacher Miss Emily had called me saying that Dayton was coughing and he sounded croupy and that he couldn't stop.  I headed over there as fast as I could.  I found Dayton coughing, super red and he wasn't able to stand because he was coughing so hard and he was out of breath.  His cough was very seal like.  I asked if there was any contact with nuts and Miss Emily stated that they hadn't even got lunch out yet.  I picked Dayton up in my arms and I rushed him to the ER.  His cough progressively worsened and by the time I arrived at the ER Dayton was limp with blue finger tips and blue around his mouth.  I ran in with Jason shortly behind.  As soon as i walked through the doors there was no waiting and they instantly took me back to a room.  ER room 14 to be exact.  They got to work on Dayton right away.  They gave him some breathing treatments along with some steroids.  They kept on listening to his lungs to find that they were clear.  It was his throat that was closing off.  The told me that if i would have waited 10 more minutes that the results would have been tragic at the rate his throat was closing. They persisted in asking if Dayton had a fever, cough, sore throat, upset stomach, or running nose.  I stated over and over again that he has been super healthy and he wasn't sick.  I told them that Dayton has asthma and nut allergies.  They pushed both of those ideas to the side and diagnosed him with croup.   I found this to be really strange because croup affects children at night... not at noon day.  Croup comes with other cold like symptoms not just all of a sudden.  Croup just doesn't instantly make a child cough and then 10 minutes later their throat closes off.   3 hours later after entering the ER we left with a few prescriptions for steroids for his throat.  I wasn't satisfied in their answers so i started my own research on what was wrong with my son. 
I called a respiratory therapist, who stated that it could have been an asthma attack that was brought on by house hold cleaners such as Lysol or an air freshener.  I talked to Dayton's allergist who stated it could have been that his nut allergies have taken an air borne affect.  But there is no definite answer or solution.  The only way we might know for sure what happened is to wait for it to happen again and look at the conditions. 
As for the croup diagnosis... Dayton never coughed, sneezed, had a fever, sore throat, had a runny nose from the moment we left the ER to almost 48 hours after. That's why this post will be called "mystery diagnosis" because that is really how I look at it.   I have arranged appointments to go to Utah for Dayton to be looked at by some specialist and we can only hope they can figure out what went on that day.