okay so I have been running for quite some time.... I am about to run my 5th marathon on sunday.  But have been dealing with what my doctor is calling an Exercise induced allergy.  my only symptom is hives.  I only break out after about 7 miles.  all my maintenace runs leave me unaffected but as soon as I go over 7 miles I get all hot and itchy.  the concern is that I will go into anaphlactic shock and not be able to breathe..... it's only been going on for about 5 weeks, and each time I run my 10 miles I my hives get a little more intense and last a little longer.

I need to run this race on sunday... too much time and energy has gone into it, to stop because of hives!!  I'm bummed out and am looking for any advice.