Ted Danson felt like a liar on 'Cheers' because of plaque psoriasis. Now he's speaking out.

BEVERY HILLS, Calif. − When you think of Ted Danson, you probably picture the charming Sam Malone behind the bar on "Cheers." Or the conniving, supernatural architect on "The Good Place."

But life for the sitcom star hasn't been all laughs behind-the-scenes. For much of his career, Danson says, he's struggled with moderate-to-severe plaque psoriasis − a chronic skin condition that had a debilitating impact on his self-esteem and made him feel like a fraud, even as his star was on the rise.

"People would come up and compliment me or think of me as Sam Malone or whatever, and I was always lying, because part of my brain was going, 'If only you knew,' " Danson says. "This is not a boohoo moment, meaning life has been very kind to me. I'm so blessed. But it does make you feel like you got to hide something, and that's not a good way to go through life."

Looking back, the actor says, he wonders if his penchant for comedic roles can be traced back to his condition.

"I sometimes wonder whether or not my self-deprecating humor came as a defense: 'I'll make fun of myself before someone else does' kind of thing," he says. "I was obviously able to navigate it, but it takes a toll."

Now, the actor is teaming up with Bristol Myers Squibb − a pharmaceutical company that makes SOTYKTU, a drug aimed at reducing psoriasis symptoms − for the “SO, Have You Found It?” campaign, which encourages people with plaque psoriasis to explore treatment options with their dermatologists.

What is plaque psoriasis? And how is it treated?

Mayo Clinic describes plaque psoriasis as a skin disease that causes itchy, scaly rashes, usually on the knees, elbows and scalp. According to the American Academy of Dermatology, about  7.5 million people in the United States have psoriasis, which is not contagious and can be exacerbated by stress. Though there are treatment options to manage symptoms, there is no cure.

Danson says his psoriasis has been up and down since he was diagnosed at 25, a common age people learn they have the disease. At its worst, he says, plaque psoriasis caused painful, itchy, red sores all over his body, usually accompanying stress or tiredness. "You can just feel not good in your skin − literally, not just emotionally," he says.

Over the next three decades, Danson tried nearly everything to fix it, including light boxes, coal tar and various ointments and diets. The process of trying to get control over his psoriasis proved "very humbling," he says, adding nothing quite worked. Mayo Clinic says people with plaque psoriasis often try different drugs or treatment combinations before they find an effective approach.

Dr. Jennifer Soung, a dermatologist partnering with the campaign, encourages psoriasis patients to take a holistic approach to treatment, of which medication is but one component.

"It is very much true that in the last 10 to 20 years, there's really been a revolution of new treatments for psoriasis, because we now understand how to target the inflammation in a more specific way," Soung says. "Sometimes I'll joke with patients that this has never been a better time to have psoriasis, because you have treatment options."

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For Ted Danson and others, plaque psoriasis takes a mental health toll

For many who struggle with plaque psoriasis, the mental health toll can be just as, if not more, debilitating than the physical symptoms. Danson says he avoided swimming or wearing shorts and stuck to long-sleeve shirts out of shame of having the condition.

"You feel victimized and betrayed by your body," he says. "You can rise above it, you can deal with it and all of that, but it's hard. It's like you're playing at a disadvantage in life."

Soung says depression often follows a diagnosis.

"It's clearly established in research that patients with psoriasis are depressed too," she says. "When they first learn, they're just overwhelmed and kind of a little bit in denial too."

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Danson says he's grateful to have had his loving and supportive wife, actress Mary Steenburgen, whom he wed in 1995, to lean on. About 15 years ago, a dermatologist introduced him to a new medication developed to treat the disease. It worked well, the actor says, adding his psoriasis has now developed into psoriatic arthritis, which causes pain to his joints but at least doesn't come with severe skin irritation. The actors regards this as an improvement. "I feel I have other issues at 76, but I'm not worried about whether I have plaque psoriasis anymore," he says, chuckling.

Danson wants others diagnosed with psoriasis to know they're not alone.

"A young man called me who I knew," Danson says, "and he was devastated. He discovered he had psoriasis. And I was able to go, 'I totally get it. I know it's embarrassing … You're lucky. You've been born at the right time that medicine has come up with something that will really help you, so don't worry too much.' … It's about empowering people to not feel victimized by this disease."

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This article originally appeared on USA TODAY: Ted Danson, of 'Cheers,' on debilitating plaque psoriasis struggle