PE is the general notation applying to all licensed engineering disciplines and is recognized as such by all the states as far as I am aware. However, some, such as Washington, Arizona, Oregon California, and Utah, to name a few, make a differentiation between Civil and Structural. In that case, the PE alone would refer to just the Civil. If there is an additional certification beyond that, it is recognized as a specialty, such as Structural.
My Washington and old Oregon license said "Civil and Structural" right on the certificate, and my old Arizona noted "Registered Professional Engineer with a Proficiency in Structural Engineering".
It would be far less confusing to the public if there was a greater level of standardization in the engineering licensing area, but that's just my opinion..
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask