erethism

from WordNet (r) 3.0 (2006)

erethism
    n 1: an abnormally high degree of irritability or sensitivity to
         stimulation of an organ or body part

from The Collaborative International Dictionary of English v.0.48

Erethism \Er"e*thism\, n. [Gr. ? irritation, fr. ? to stir,
   rouse, fr. ? to stir: cf. F. ['e]r['e]thisme.] (Med.)
   A morbid degree of excitement or irritation in an organ.
   --Hoblyn.
   [1913 Webster]