The Collaborative International Dictionary of English v.0.48:

Intertrigo \In`ter*tri"go\, n. [L., fr. inter between + terere,
   tritum, to rub.] (Med.)
   A rubbing or chafing of the skin; especially, an abrasion or
   excoriation of the skin between folds, as in fat or neglected
   children.
   [1913 Webster]

WordNet (r) 3.0 (2006):

intertrigo
    n 1: chafing between two skin surfaces that are in contact (as
         in the armpit or under the breasts or between the thighs)