Coulrophobia is a neologism, that is, a fairly new term that has not yet come into popular usage. Although fear of clowns is well documented, there is no precise term for it in medical language yet. But this is the most popular -phobic term for fear of clowns.

Some people find oversized hands and feet, exaggerated facial features, and bizarre clothing humorous. Others see it as simply grotesque. Young children in particular have a universally negative reaction to clowns, as a psychology professor at California State University, Northridge stated, young children are "very reactive to a familiar body type with an unfamiliar face".

In recent years some totally evil clowns have shown up in film and literature.

Twisty the clown in "American Horror Story."

Stephen King's Pennywise from "It."

Spawns nemesis "Violator."

And of course there are the "Killer Klowns from Outer Space."

These characters may have helped spread coulrophobia, or may be a response by authors of a larger awareness of this phobia.

But bad clowns aren't particularly new. Witness Harlequin, The King's Fool and Mr. Punch. (Punch and Judy)

Ben Radford, who published the book "Bad Clowns" in 2016, argues that most people are not afraid of clowns. In fact clowns are much-loved.

So perhaps coulrophobia is not spreading, it's just getting more publicity than ever before.

More Info: en.m.wikipedia.org