I had to first look up definitions, then I'm still not a whole bunch clearer, but here are some sites I've found.
Definition Immunologist:
http://www.aaaai.org/springallergy/2003/whatis.stm
Definition Allergist:
http://www.allergychannel.net/allergist.shtml
Immunologist Assn's Doc finder:
http://www.clinimmsoc.org/referral/
Allergist Doc Finder:
http://www.acaai.org:80/LocateAllergist/
I found no Immunology or Allergy assessments in the US News Top Hospitals:
http://health.usnews.com/sections/health/best-hospitals
But they do assess Rheumatology...At least if there isn't a TOP hospital in your area, there mite be a rheumy who's trained at one.
I also came across this about docs which is off this particular aspect but is about docs and finding one/or firing one:
http://www.cnn.com/2007/HEALTH/08/16...doc/index.html
Hopes this all helps! - j