The 30-year-old star - who is expected to marry fiance Kris Humphries on August 20 - was upset after a dermatologist diagnosed the skin condition after she went to a consultation about an itchy, flaky, red rash.
In scenes shown on reality TV show `Keeping Up with the Kardashians` last night (24.07.11), Kim told the skin specialist, Dr. Harold Lancer: "I cannot have psoriasis. I`ve heard of it before, because my mom has always had it. She didn`t have red flaky dots all over.
"My career is doing ad campaigns and swimsuit photo shoots. People don`t understand the pressure on me to look perfect. When I gain a pound, it`s in the headlines. Imagine what the tabloids would do to me if they saw all these spots."
The doctor advised Kim to take things easy as stress can trigger flare ups in the condition, which is believed to be caused by environmental factors and genetics.
He told her: "The number one way to help yourself is lead an easier, slower pace life."
Despite her initial shock, Kim later revealed she had consulted her mother Kris Jenner on coping with the condition.
She tweeted: "[My sister] Khloe freaks me out saying it`s ringworm, but it turns out I have psoriasis!! My mom has had psoriasis for years, so it`s good that I can talk to her about it."