Can someone be allergic to one breed of dog and not another breed? we have a lab and son was fine we got a beagle and has been coughing a lot

Yes...: There is evidence to suggest that people can be more allergic to certain breeds. If my dog allergic patients really want to get a dog for the family I usually have them do a "trial run" with a certain breed for a few weeks to see if symptoms develop. Cat dander on the other hand seems to be more universal with little variation of different breeds.