This person has a wart (verruca) that has built up a cutaneous horn which is made up of hard keratin. This does not slough-off like normal skin cells.
Review Date: 11/20/2012 Reviewed By: Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.