A rash spotted on President Donald Trump's neck is trending across social media and now his personal doctor is explaining what's behind it.

On Monday, President Trump made an appearance at a Medal of Honor ceremony at the White House, where the rash, which could be seen on the right side of his neck, was first spotted. The reddish spot on his neck was photographed extending above his collar.

Dr. Sean Barbabella, Trump's physician, told CNN in a statement that the rash is because of a cream he is using as a "preventative skin treatment."