[Chemar]

My son had a horrible and persistent Crohn's flare, despite doing all the good things to keep things subdued and stable

While researching possible triggers for this, I came across info I had never seen before suggesting that Crohn's may be more prevalent in people who were born during measles epidemics (my son was) or who reacted badly to measles vaccine (my son did) or had been infected with "wild" measles in early life....

one theory I saw suggests that

Crohn's disease may be a chronic granulomatous vasculitis in reaction to a persistent infection with measles virus within the vascular endothelium

http://www.gastrojournal.org/article...467-0/abstract

there are numerous other studies and articles when one starts searching

Perhaps this could explain the sudden flares that seem to come out of nowhere? Maybe the measles is activated and the system reacts? Just thinking aloud here.....