The Collaborative International Dictionary of English v.0.48:

Epithem \Ep"i*them\, n. [L. epithema, Gr. ?, fr. ? to lay or put
   on: cf. F. ['e]pith[`e]me. See Epithet.] (Med.)
   Any external topical application to the body, except
   ointments and plasters, as a poultice, lotion, etc.
   [1913 Webster]