Though the scientific community can't determine an exact cause for this fear, many concur it likely stems from a biological revulsion. While tiny holes themselves might not pose any real danger, some believe the image of them triggers a biological response inducing fear. Some theories propose that clustered holes depict chaos run rampant, while others believe a tryphobobe's brain simply associates these clusters with disease and inflammation.
Often the flashpoint of many a phenomenon, the Internet has largely been blamed for the rise in trypophobia. A subreddit for trypophobes boasts over 20,000 subscribers who post photos of anything ranging from architecture to French bread. While "irregular holes" can definitely be found amongst these images, people are more inclined to cringe at them rather than openly fear them. If you think about it, no arachnophobe wants to look at spider photos, so why do trypophobes go to such great lengths to look at images that "scare" them?