From the introduction:
Appearing as shuffling pale bodies, having bloodshot eyes, and dark hair. These are the forms of the abominations. Commonly produced as the bastard child of a zombie and a human, these walking embodiments of hate and evil take from both sides, never looking fully zombified, or fully humanoid. All Abominations have dark hair and eyes, and pale or blue skin. Some Abominations have been known to have white hair, though this is uncommon, and is usually dyed that way.