What is the difference between bacitracin zinc and neosporin? why do doctor prefer bacitracin more than neosporin? how can you tell when to use which?

Bacitracin is a brand-name drug that contains the active ingredient bacitracin only. Neosporin is the brand name of a combination drug with the active ingredients bacitracin, neomycin, and polymyxin b. Neomycin frequently causes allergic reactions of the skin called contact dermatitis, and that's why they probably prefer Bacitracin. ref: google.com