The Collaborative International Dictionary of English v.0.48:

Desudation \Des`u*da"tion\, n. [L. desudatio, fr. desudare to
   sweat greatly; de + sudare to sweat.] (Med.)
   A sweating; a profuse or morbid sweating, often succeeded by
   an eruption of small pimples.
   [1913 Webster]