Why do people have trypophobia?

[ShannyWanny :D]

I was looking at a facebook page and the posted a bunch of pics to scare trypophobic people and I got so sick and scared, why is this scary to people?

[onereality]

Huh?

[Ryou]

Speaking specifically of those facebook pages, we are usually more likely to experience fear in a particular moment if others around us are fearful. So if there are a few thousand people grouped together talking about being afraid of something, others might look at it and feel the same way even if they didn't really feel that way before.
And fear and disgust often go hand in hand. Spiders, blood, mice, vomit, etc are things that arouse strong disgust and revulsion in people and are triggers for the fear of illness. The same could be true for little holes, especially in natural objects where they seem particularly out of place. We’re disgusted by pockmarked objects because they don’t look quite “right”; these perceived deformities signal danger, which we manifest as revulsion. Many pictures related to trypophobia look like reminiscent of parasites and or some kind of disease.
And of course, traumatic experiences can cause related fears.