Donald Trump displayed mysterious red marks on one of his hands at a recent public appearance.
The internet guessed that it could be caused by "hand herpes" or a hard fall.
A dermatologist said the hand marks were probably rashes and could be caused by many things.
Former president Donald Trump displayed mysterious red marks on one of his hands when he left his New York residence on Wednesday to attend E. Jean Carroll's second defamation trial.
While it's difficult to diagnose a skin condition from just one photo, Dr. Joshua Zeichner, an associate professor of dermatology at the Mount Sinai Hospital in New York City, told Business Insider that Trump most likely had a rash — which could be caused by almost anything.
"Rashes on the hands can be caused by a variety of factors, ranging from infections to inflammatory conditions to external exposures," Zeichner said.
Zeichner shared four possibilities for the rashes on Trump's hand, all of which are probably less interesting than what the internet is theorizing.
Possibility 1: His hands are too dry
Zeichner said the most common causes of hand rashes were dryness and overwashing. Given that Trump is a self-proclaimed "germophobe," the excessive-handwashing theory could check out. Cold temperatures can also lead to dry skin, which is more common in the winter.
Possibility 2: Blisters from playing golf
Another possibility is blisters, which Zeichner said could be caused by "friction from activities like golf, weightlifting, or baseball." Since Trump is known to golf a lot, this is also a plausible scenario.
Possibility 3: He got lime juice on his hands
Zeichner said that "even lime juice exposure in the presence of sunlight can cause a chemical burn to the skin," otherwise known as "margarita burn." While Trump doesn't drink alcohol, a citrusy mocktail could cause the welts.
Possibility 4: None of the above
As Zeichner pointed out, hand rashes can be caused by almost anything, including something as unsuspecting as bug bites. Unless the former president confirms what caused the marks, we may never actually know.
Read the original article on Business Insider