Her worst moment came when she had an argument with a former boyfriend and he complained about her flaking skin "all over my bed and floor."
"Do you think I can control this?" asked Ferrerya. "People have told me that they couldn't get their nails done or get a haircut because people thought they were contagious. They don't know what it is and you are too scared to tell them because you think you will be rejected. There's a lot of ignorance out there."
Psoriatic arthritis can develop a decade after the skin condition is first diagnosed, according to Arthur Kavanaugh, a rheumatologist and professor of medicine at the University of California, San Diego.
Only about 25 percent have spine involvement, and it can affect the joints of the hand, the feet and often the Achilles tendon or other tendons or ligaments. It tends to run in families and is associated with a group of genes, now called the "psor genes," he said.
"It's among the stronger genetic diseases in rheumatology," said Kavanaugh. "The immune system forgets and attacks itself."
As in Ferrerya's case, it can also produce "sausage" fingers or toes -- swelling beyond the joint. One of the better known patients with psoriatic arthritis is golf player Phil Mickelson.
"Nobody wants anyone to be sick, but health is political and it certainly helps to have famous people either champion of have the disease," said Kavanaugh.
Although the disease is not curable, there are many treatments to keep the disease at bay, such as topical steroidal creams and systemic medicines called "biologics" that work on the immune system.
Because of the psoriatic arthritis, Ferrerya takes anti-inflammatory medication, but she has also found that changing her diet -- eliminating certain fruits and vegetables -- has helped. As with all psoriasis patients, she also finds relief by exposing her skin to the sun.
Ferrerya has also become active in the National Psoriasis Foundation, whose mission is rooted in support.
When founder Beverly Foster, who suffered from severe psoriasis, turned 30, her husband gave her a unique gift. He put a small classified ad in a Portland, Ore., newspaper in 1966, asking those with the disease to call his wife so she night have someone to talk to.
Foster received more than 100 calls and began organizing meetings and in 1968. That's how the foundation aimed at raising money for research was born.
But despite the national attention that Kim Kardashian brought to the disease, psoriasis still evokes derision, according to foundation spokeswoman Coman.
Though much of the reaction to Kardashian's revelations was positive, some television commentators sarcastically wondered why the big deal, when "all she has is dandruff of the leg."
"We've been monitoring the blogs and postings and people's responses have been horrid," she said. "Even some [television hosts] were saying [Wednesday] she must have an STD [sexually transmitted disease]. But psoriasis is an autoimmune disease and you wouldn't say that about someone with type 1 diabetes. That sets off a whole cycle of wanting to cover it up."
Still, Ferrerya is thrilled that Kardashian spoke up.
"People view psoriasis as such an ugly disease," she said. "And now a nice pretty girl who has all the money to buy expensive treatments, for her to come out on her show and have her moment -- the one all of us had when we were diagnosed -- it's fabulous."