NATIONAL HARBOR, United States (AFP) - US President Donald Trump made a rare public comment on his enigmatic straw mane on Friday (Feb 23), jokingly admitting that he suffers from male-pattern hair loss - a bald spot.

"I try like hell to hide that bald spot folks, I work hard," Trump quipped during a speech to conservatives just outside Washington, in an unusual flash of self-deprecating humour.

"It doesn't look bad, hey, we're hanging in," he added, giving a swirl to the cheering audience.

Trump's elaborate combing regimen has long been the butt of jokes and speculation.

A tell-all book about Trump's White House claimed his daughter Ivanka was in the habit of describing the mechanics of the combover to friends: "An absolutely clean pate - a contained island after scalp-reduction surgery - surrounded by a furry circle of hair around the sides and front, from which all ends are drawn up to meet in the center and then swept back and secured by a stiffening spray."