diff --git a/nbconvert/nbconvertapp.py b/nbconvert/nbconvertapp.py
index 76a66648d..0745926e8 100755
--- a/nbconvert/nbconvertapp.py
+++ b/nbconvert/nbconvertapp.py
@@ -555,7 +555,7 @@ def document_config_options(self):
                 sections += ".. image:: _static/{image}_inheritance.png\n\n".format(image=category)
             sections += '\n'.join(c.class_config_rst_doc() for c in categories[category])
 
-        return sections
+        return sections.replace(' : ',r' \: ')
             
 #-----------------------------------------------------------------------------
 # Main entry point