There isnt a rank but some programs are more prestigious than others for different things. Think Duke for peds immuno, Sinai for food allergy, UCSD for mast cell. Any program will train you to be a good allergist it comes down to fit. However, in the academic world I think most fellows/allergy attendings would agree that BWH NIH National Jewish Penn Hopkins are all around some of the best from an academic/research standpoint but it depends on what you want to do with your career. If you want to do private practice like myself lol where you go for allergy training literally doesnt matter the only time it kinda matters is if you want to practice in California it would be in your best interest to do your allergy training in California (from the PP standpoint training in the area you want to practice helps). For academics, prestige/name sorta matters to an extent ie if you want to have a research career and publish/innovate the field/make a name for yourself youre probably better off coming from a place like Hopkins or Stanford than say Penn State or Rutgers despite all four training you to be an excellent and competent allergist