The Collaborative International Dictionary of English v.0.48:

Variolous \Va*ri"o*lous\, a. [LL. variolosus, fr. variola the
   smallpox: cf. F. varioleux.] (Med.)
   Of or pertaining to the smallpox; having pits, or sunken
   impressions, like those of the smallpox; variolar; variolic.
   [1913 Webster]

WordNet (r) 3.0 (2006):

variolous
    adj 1: relating to small pox [syn: variolar, variolic,
           variolous]