A self-described germaphobe, the 45th president is strictly enforcing proper hygiene inside the White House — and wherever else he goes.

He asks visitors if they’d like to wash their hands in a bathroom near the Oval Office.

He’ll send a military doctor to help an aide caught coughing on Air Force One.

And the first thing he often tells his body man upon entering the Beast after shaking countless hands at campaign events: “Give me the stuff” — an immediate squirt of Purell.

Two and a half years into his term, President Donald Trump is solidifying his standing as the most germ-conscious man to ever lead the free world. His aversion shows up in meetings at the White House, on the campaign trail and at 30,000 feet. And everyone close to Trump knows the president’s true red line.

“If you’re the perpetrator of a cough or of a sneeze or any kind of thing that makes you look sick, you get that look,” said a former Trump campaign official. “You get the scowl. You get the response of — he’ll put a hand up in a gesture of, you should be backing away from him, you should be more considerate and you should extricate yourself from the situation.”

The president’s admitted germaphobia has been a fixture throughout his career — from real-estate deal rooms to casino floors — and it’s now popping up in more public ways. It could create another round of tactile challenges as Trump launches his 2020 campaign, during which he might try to steer visitors toward his signature thumbs-up selfies and away from handshakes for the next 16 months.

The president’s hatred of involuntary bacterial emissions burst into the open last month when his acting chief of staff, Mick Mulvaney, started coughing in the Oval Office while ABC’s George Stephanopoulos was interviewing Trump. “I don’t like that, you know. I don’t like that. If you’re going to cough, please, leave the room,” Trump said before shaking his head.

White House aides have said the president is simply displaying common sense: Trump keeping his hands clean is a good way to avoid getting him, or his staff, sick.

Indeed, many presidents have sought to avoid germs, using hand sanitizer and taking other precautions after shaking many hands over the course of a day. But Trump often takes the practice to an extreme.

White House staffers know that if they’re visibly sick or sound hoarse, they must steer clear of a president who doesn’t want to be around anyone who’s under the weather.

“It was serious that you shouldn’t spend much time in front of the president [if you were sick] because he would be extremely annoyed by that,” someone close to the White House said. “He doesn’t want to get sick. ... Everyone understood that if you were sick or sounded sick, your involvement in front of the president should be extremely limited.”

Sniffling staffers have been told they should take a break to drink some tea or otherwise get cleared up before going into the Oval Office, this person said.

Trump has a long history of germaphobia, which has sometimes hurt his business. Jack O’Donnell, a former president of the Trump Plaza casino in Atlantic City, N.J., recalled how Trump didn’t do well with some customers in the late 1980s — because he hated shaking their hands.

“Customers wanted to be around him and they didn’t understand when he didn’t shake their hand,” he said. “They would be like, ‘What a rude guy. I put my hand out, and he turned it down.’

“People would approach him as he’d walk through the casino to get to the offices and he hated that they touched him,” O’Donnell said. “He was always that way.”

Trump has even admitted that his germaphobia “could be a psychological problem,” as he told Howard Stern during a 1993 interview in which he also said he washes his hands “as many times as possible” during the day. He also told Stern in 2007 that he was even afraid of his own child — Barron Trump was a baby at the time — when he became sick.

“When he has a cold, I just keep him away from me,” he said, and then laughed with Stern.

On the 2016 campaign trail, new staffers were told not to cough or sneeze if they were in a room with Trump, said a former campaign staffer, who added that Trump and germs became a running joke among staffers. “We were surprised that somebody who had such an issue with germs would ultimately run because you have to shake so many hands,” the former staffer said.

During the campaign, then-spokeswoman Hope Hicks often offered Purell to Trump — and he made frequent use of it, according to a former campaign official.

More recently, Trump has used his germaphobia advantageously — as a shield to rebut salacious, unverified “golden shower” claims about his alleged 2013 behavior at the Ritz-Carlton in Moscow.

During the presidential transition, right after BuzzFeed published the so-called Trump–Russia dossier — produced by former British spy Christopher Steele — that included those allegations about Trump’s conduct in Moscow, Trump said at a combative news conference: “Does anyone really believe that story? I’m also very much of a germaphobe, by the way, believe me.”

He hasn’t changed much as president, even with a very public job that entails him meeting people throughout the day, including world leaders who he must treat respectfully in diplomatic dealings. But even when guests he knows come to the Oval Office, Trump sometimes hesitates to initiate a handshake, leading people to extend their hands to get one.

“When you’ve been around this guy a lot, you know how it’s going to go. You’re in there and somebody will walk in and put their hand out and you’re just thinking to yourself, ‘Uh, that’s a mistake,’” a former campaign official said.

Although his love for fast food and soda is widely known, Trump religiously follows protocols from the Centers for Disease Control and Prevention on one aspect of his health: Washing his hands before eating, according to someone who has seen him do that multiple times. In the Trump White House, dining room attendants often bring out sanitary hand wipes along with dinner for the president.

A stash of Purell is kept outside the Oval Office. During the photo lines at White House Christmas parties, Trump likes to use hand sanitizer in between shaking people’s hands, according to a former White House staffer.

Trump’s personal aide, or “body man,” carries a bottle of hand sanitizer at all times. Before Trump eats or after shaking hands during meet-and-greets, Trump sticks out his hand to get a squirt of it, according to a former White House official.

Trump’s germaphobia has created challenges up in the air. Even though Air Force One is a state-of-the-art aircraft, it’s still a metal tube in the sky — a prime vector for germs due to the number of people moving through tight quarters. White House staffers avoid going near the president — and some have avoided even going on trips — if they have a cold.

And when someone coughs or sneezes in Trump’s presence on Air Force One, he’s been known to quickly assume the worst. “Are you sick?” he has asked, according to the person close to the White House.

In July 2017, during Anthony Scaramucci’s brief White House tenure, the communications director had a sore throat and was coughing on an Air Force One flight to Ohio. Trump noticed and told Ronny Jackson, the White House physician at the time, that Scaramucci wasn’t feeling well and ordered him to go check him out.

Plenty of aides have joked that Trump is a germaphobe, Scaramucci said. But even more, Scaramucci added, “He’s a ballbuster."

"If you’re standing by him, and you’re going to look at something on his desk, and you lick your index finger to open the thing to try to catch an edge on the paper, he’ll smack your hand and be like ‘What are you, disgusting?’” Scaramucci said.

Some Trump aides have said they think Trump is now in on the joke himself — at least with some senior officials.

In the Oval Office in 2017, Agriculture Secretary Sonny Perdue coughed in a meeting and Trump was “all grossed out, but it was more joking rather than angry,” said one former senior administration official with knowledge of the incident. “He was like, ‘Ahh, you’re going to get me sick, move back.’ He kind of yelled at him, like, ‘You’re going to get me sick!’” Read more at Politico