In some entries the word Doctor is replaced by the abbreviation, Dr , e.g. Dr Scholl’s , Dr Seuss . This is the usual written abbreviation in British English. In American English the form Dr. is always used.
DOCTOR
Meaning of DOCTOR in English
Oxford guide to British and American culture English vocabulary. Руководство по британской и американской культуре, Оксфордский английский словарь. 2005