Ecthyma (Contagious)

Contagious ecthyma is a focal skin lesion caused by orf virus infection, usually occurring on a finger and transmitted to animal workers from sheep or goats. The lesion passes through 6 stages; this image shows the 2nd "target" stage, characterized by a large nodule with a red center surrounded by a white ring and a red periphery.

Image courtesy of the National Institute for Occupational Safety and Health's Occupational Dermatoses web site (http://www.cdc. gov/niosh/ocderm.html).