Kim Kardashian & Kanye West -- HICKEY CONFIRMATION

Psoriasis, Shmoriasis ... TMZ has uncovered THE TRUTH about the suspicious mark on Kim Kardashian's neck ... and it DEFINITELY originated from Kanye West's mouth.

Sources close to Kim's neck confirm ... the red blotch was NOT the result of Kim's skin condition ... it's totally a hickey.

It all makes sense, considering the mark was first seen the day after Kim and Kanye went on a movie date in NYC.

Which reminds us ... tips for hickey removal that may or may not work: