It is possible to get the human immunodeficiency virus (HIV, the virus that leads to AIDS) from sharing cutting instruments — such as a needle or knife — that might have the virus on them. The virus that causes hepatitis also can be spread through cutting.
Many other dangers apply to cutting, too. Cutting can become a habit for some people — it can seem like an addiction that they can't stop. Cuts can be deeper than intended, cause scars, or become infected.
Cutting usually is a sign that someone has deep emotional troubles that he or she doesn't have the skills to deal with in a healthy way. That's why it's important to get help to overcome the urge to cut and deal with the problems that bring it on.