The Collaborative International Dictionary of English v.0.48:

Xeroderma \Xe`ro*der"ma\, n. [NL., fr. Gr. xhro`s dry + de`rma
   skin.] (Med.)
   (a) Ichthyosis.
   (b) A skin disease characterized by the presence of numerous
       small pigmented spots resembling freckles, with which are
       subsequently mingled spots of atrophied skin.
       [1913 Webster]

WordNet (r) 3.0 (2006):

xeroderma
    n 1: a mild form of ichthyosis characterized by abnormal dryness
         and roughness of the skin [syn: xeroderma, xerodermia]