There are a number of words in Italian that end in consonant, but they are mostly coming from Latin/Greek/Other or are contractions of other words (or articles/particles). But while their origin is foreign, they are not simply "loan words", but proper parts of the language:
Tram, pancreas, Nord Sud Ovest Est, Un, il, gratis, gas, etc...
So, according to where you draw the line, all "Italian" words end in vowel. But articles are a prime example of non-loan words/foreign origin that don't, if you count them as words
I'd like to point your attention to this quora answer, in particular, which describes the topic in details.