The lawsuit was filed in Baton Rouge by the Institute for Justice, a libertarian group that says "job-killing" and arbitrary state licensing has imposed burdens on workers, employers and consumers around the country.
"I can't find licensed estheticians who know how to thread," said Lata Jagtiani, a native of Gujarat, India, who came to the United States in 1985 and has lived in Louisiana since 1996.
State inspectors fined Lata and Deepak "Jack" Jagtiani $4,900 and threatened to close the couple's Threading Studio and Spa in suburban New Orleans because two of their workers are not licensed estheticians, according to the suit.
"I know my job and have very good technique ... but now I don't have a job," said Panna Shah, one of the former employees, at a news conference.
The event was livestreamed from the Metairie salon by the Institute of Justice, which, playing on a Revolutionary War slogan, posted "Don't thread on me" on its Facebook page.
"Shah has been threading for 34 years" and fellow plaintiff Ushaben Chudasama for 28, and customers often ask for them "and for other unlicensed threaders because they are experts at what they do," the lawsuit said.
It said Chudasama is now a part-time receptionist at the salon and Shah is working in retail. Neither is making nearly as much money as they did from threading, even though threading appointments typically cost customers only $10 to $20, according to the lawsuit.
Threading — a technique popular in Asia and the Middle East — plucks hair by pulling twisted thread along the skin, rather than tweezing hairs out one at a time.
In Louisiana, threaders need an esthetician's license, which requires 750 hours of beauty school courses and three licensing exams.
At least 250 of those hours "are for sanitation, health and cleanliness, and all of these other things that we must teach for people to run a healthy and clean shop," said Stephen Young, director of the Louisiana State Board of Cosmetology. He and the board's members all are defendants in the lawsuit.
He said hair removal, whether with tweezers or thread, falls under the board's reason for existence: "the health and safety of our citizens."
The Institute of Justice says it has "needless red tape" around the country, with states requiring anywhere from four months in Pennsylvania to two years in Hawaii to meet educational and experience requirements for 102 low- and medium-wage jobs.
According to a 2015 analysis of occupational licensing by the Obama administration, some of these requirements, such as for doctors and pilots, can be important for health and safety, but many others are inconsistent and out of sync with the skills today's economy needs.
Last year, the nonprofit won a 6-3 Texas Supreme Court ruling against a similar law. The Texas high court noted that Texas cosmetology schools must provide 25 hours of instruction in hair removal, but fewer than 10 of the 389 approved schools teach threading.
Texas officials said 430 hours were unrelated, though the plaintiffs said that figure was low, the majority noted.
"That means threaders are required to undergo the equivalent of eight 40-hour weeks of training unrelated to health and safety as applied to threading," it said, making the 750-hour requirement "oppressive" and a violation of the Texas Constitution.
The Institute of Justice also won a 2013 lawsuit for the monks of St. Joseph Abbey, who had been told they could not sell caskets because they were not licensed funeral directors.
And in 2010, Louisiana reduced florists' licensing requirements after a challenge by the same group, eliminating a requirement for a demonstration exam but keeping a requirement for a written exam.