There were at least two lines of Swanns in the Baltimore area. One involved a Baltimore Mayor Swann. I have not been able to connect to that line.
My only Dorthy or Dorthea Swann was much older than the one you are seeking, but perhaps there could be a slim chance of a connection.
Dorthy or Dorthea (depending on census spelling) Campbell was born in Virginia before the Civil war. She had two sons Edward M. Swann, b.1843 and George Francis Swann. b.1845. Both fought in the Civil War and both ended their days in the Baltimore area. Edward died in a soldiers home in Baltimore. I don't know if he had a family and I can't yet find any records of such a soldiers home.
My wife's line is through George Francis Swann who married Anna Eliza Lewellyn of Richmond, VA. They had five daughters born from 1872 to 1885 and only one son Samual Amory Swann, b.3/25/1885. He had only one daughter that I know of: Elizabeth Shipley Swann, b. 9/11/1921 who married a Mr. Eugene Morgan Lilley(now deceased). Elizabeth is still living with her daughter somewhere in Severna Park, MD.
I've talked to her about the Swanns several times. She remembers visiting Edward at the Baltimore Soldiers Home, but she didn't seem to know much about him or the other Swann line.
Hope that you find something to help.