How do I automatically contact an admin when something gets marked as spam?

Specifically, when the sitewide contact form is used and the submission is marked as spam automatically, I cannot find any way to notify an admin by email. When new content is posted or a comment is made on a node, I have a trigger (independent of the Spam module) that sends an email so I can go check it out. What I am looking for is a way to have a notification email sent to an admin when anything is marked as Spam automatically regardless of if it's a comment, node, sitewide contact, or personal contact. How can I do that?