Donald J. Trump’s hair is the latest point of contention between Gawker Media and Hulk Hogan’s lawyers.

In a letter sent last week to Gawker on behalf of a hair treatment clinic, Charles J. Harder, who is representing Mr. Hogan, the retired wrestler, in his invasion of privacy lawsuit against the media company, said a recent article about Mr. Trump’s hair made “numerous false and defamatory statements about my clients.”

Mr. Harder demanded that Gawker immediately remove the article and publish a public apology and full retraction. The letter also threatened legal action on behalf of the clinic, Ivari International, and Edward Ivari.

Image Terry Bollea, the TV personality known as Hulk Hogan, with his lawyer Charles Harder. Credit... Gerardo Mora/Getty Images

The letter continues a legal battle between Mr. Harder and Gawker. His Los Angeles-based law firm, Harder, Mirell & Abrams, was thrust into the spotlight last month when it was revealed that the Silicon Valley billionaire Peter Thiel was secretly providing financial support for lawsuits against Gawker.