The Associated Press reported Spade was found with a red scarf around her neck attached to a doorknob. Kate Spade New York tweeted an image, saying "We honor all the beauty she brought into this world".
Designer L'Wren Scott was found dead in her New York City apartment in March 2014 at the age of 49.
The company says in a statement that while Spade had not been affiliated with its "beloved brand" for more than a decade, she and her husband were its founders, and the news of her death is "incredibly sad". The company later expanded to sell clothing, accessories and household items.
Spade sold a good chunk of the company in 1999 and the remainder of it in 2006 before walking away in 2007. They started a new venture in 2016, called Frances Valentine, selling handbags and footwear.
In 1986 Spade started working at the fashion magazine Mademoiselle, climbing the ladder until she became a senior fashion editor.
Some of those paying tribute to Spade recalled their first experience with the brand, once perceived to be a status-symbol.
As CNN put it, "For many women, a Kate Spade handbag functioned as a symbol of professional achievement".
The couple's 13-year-old daughter was at school.
In 2017, Coach (now Tapestry) bought the Kate Spade label, the last remnant of Liz Claiborne, in a deal worth $2.4 billion.
Many celebrities also took a moment to shine a light on mental illness while sharing their condolences.
Today, Hauser has other Kate Spade purses that are more colorful and fun.
Writer Melanie Hauser, who writes as Melanie Benjamin, always felt a Kate Spade bag was aspirational - just out of reach.
Singer Josh Groban sent "love to her family" and said that "depression does not discriminate and comes without warning", while tweeting the phone number for the National Suicide Prevention Lifeline.
"Fuzzy picture but I love it. Kate and I during Christmas family photos". Kate Spade.' I loved Olive for some reason. "My heart goes out to her family and to all she has touched". "You see someone who kind of made a career off of making people smile", she said.
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