IDE written in Perl? Surely that must be Padre.

That's probably because it's the *only* one that is...

Bottom line: Perl doesn't need an IDE, as it arrives with both the compiler and the debugger. Throw in a mature editor and you're all set. Adding said editor will also benefit any needs for a more "integrated" environment, as most editors now come with an apt collection of configuration tools for any development needs.
If you *really, really* need a GUI for the whole debug process, the Devel::ptkdb tool will satisfy that need.

And as a bonus prize, you get to become a developer whose way of thinking isn't limited by the tools he use.