Lawyers for Beauty Concepts LLC fired off a cease and desist letter to KK's legal team, claiming since July 2017 it's provided salon and skin care services under its SKKN+ brand name, owned by Cydnie Lunsford.

In the letter, obtained by TMZ, Beauty Concepts says it also operates a website and social media handles using the same block letters. What's more ... Beauty Concepts claims it applied to the U.S. Patent and Trademark Office back in March to register the SKKN+ logo.

The company claims it's invested considerable time, effort and money to develop and market its SKKN+ services over the last 3 years, and Kim's play for the same name would cause confusion in the marketplace.  Them's magic words, because it's the basis on which the Patent and Trademark Office would reject an application.

Kim's attorney, Michael G. Rhodes, tells us, "We certainly appreciate and support small businesses, and our hat is off to Ms. Lunsford. But the question at hand is one of trademark law and we’ve not done anything deserving of legal action by her."

He continues, "We are disappointed that she has chosen to run to the media knowing that we were scheduling a call for tomorrow, requested by her attorney. So while disagreeing with the letter, we’re hopeful that we can smooth things over once both sides speak.”

In the legal letter, Beauty Concepts says Kim's trademark application for "SKKN" is a ripoff of their innovative moniker and simply adding "By Kim" does little to differentiate the brands.

What's more ... Beauty Concepts says it has used the SKKN+ name for 3 years before Kim's company applied for its trademark.

As we've reported ... in addition to filing for the trademark, SKKN.com and @SKKN social media handles were all locked down by Kim's team in December 2020 ... indicating this had been in the works for a while.