Swedish and German, a variant or diminutive of Katarina, the pan-European form of Katherine, from Greek "pure".

Popularised in the US, Karen and to a lesser extent Karin were introduced into the UK from about the middle of the 20^th century. The spelling is very variable - a fullish list is given under Karen.

A correspondent [KC] reports that her name, Kareen is an Anglicized spelling of the German pronunciation of the name Karin.

It is not clear if Carina is truly a derivative.