The 35-year-old confessed she has to go through the procedure of getting a cortisone injection into her posterior every few years because she has psoriasis, a skin condition which causes red, flaky patches which can become itchy or sore.
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"Every few years I get a cortisone shot. I just got one as my psoriasis was so bad in Vegas. That's a little unknown fact of me, I have to get cortisone shots every few years," Kim wrote on her official website.
Kim first learnt that she had the condition when her mother Kris Jenner spotted a rash on her leg.
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But after Kim, who has children North, three, and Saint, eight months, with husband Kanye West, had her first cortisone shot, speculation spread that she had had butt implants.
"I went to go get a cortisone shot in my butt. I lived right behind Kitson (a boutique). One of my neighbours was a dermatologist at Cedars (Cedars-Sinai Hospital). I go in there and he's like, 'There's a one in a billion chance that you will get a huge indent in your butt.' Of course I get a huge indent on my butt," Kim said.
"There is a picture of me in Miami wearing an electric blue dress, and another picture of me walking down Robertson," she added.
IANS