And by the way neither Italians or Spanish started off with dark hair and darker complexion, it wasn't until after the Moors (arabic) invaded southern Europe and occupied and interbred with the natives that they took on those features. Before that they were pale haired and mostly fair skinned. And hispanics by the way are nothing more then Native American (be it meso, or south american) mixed with european (ie spanish) stock in the first place. .
Interestingly enough, in the Scots and Welsh Celts, there's a long history of "black Celts", folk with a very swarthy complexion, compared to the normal very pale Celtic skin.
Alas that's been taken up by some folks claiming black African's ruled a mythic country here...oh boy
... Facts are more likey to be Phoencian and Greek traders and thier slaves as the root of that difference.
Likewise, the Anui of Japan are another ethnic oddity.
Races in fantasy worlds could have all kinds of natural or magical variations and adaptations.
-BLue-tinged humans who have copper for blood (or green if you like Vulcans
)
-Smooth skin, they don't sweat (useful adaptation for Athas perhaps).
And so on. Colour is just one of the many variables.
Also, having race being an issue
is logical. Not necessarily in the xenophobic ways of our world, but in taboos and abilities, for example:
the Derial people have unusually large blue irises, and are the only folk who have the ability to be sorcerors.
or, by Imperial proscription, only the people of the island of Valmer maybe priests of the fire god, for their skin is black and have hair like copper, which pleases the god (well, pleases the Imperial culture's philosophy, in reality).
er, derail off