Whenever my toddler gets very upset or throws a fit, he has a tendency to rake his fingernails very hard across his face, often drawing blood. Currently one side of his face is covered with scratches and scabs from this behavior. How can we encourage him to stop?

The first, most obvious idea is to simply trim his nails very short, but I'm worried that might just displace his frustration and cause him to start pulling out hair or something similar.

**Edit**: Two years after I originally asked this question, our child was formally diagnosed with autism. I add this here because it seems like an important point for people to keep in mind. An extreme inability to deal with ordinary stresses, including self-harming behaviors, may be an indicator of problems beyond simple toddler obstinacy.