This is a great photo gallery of dermatitis herpetiformis rashes from the University of Iowa:
http://www.lib.uiowa.edu/hardin/Md/d...etiformis.html
Other Resources:
Emedicine
http://emedicine.medscape.com/article/1062640-overview
Celiac Sprue Association on DH
http://www.csaceliacs.org/dh_defined.php