Trypophobia

Trypophobia is a claimed pathological fear of holes, particularly irregular patterns of holes. The term was coined in 2005 from the Greek τρύπα (trýpa) "hole" and φόβος (phóbos) "fear". Thousands of people say they have the condition. It is not recognized in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM) or other scientific literature.
Arnold Wilkins and Geoff Cole of the University of Essex's Centre for Brain Science were the first scientists to investigate trypophobia. They believe the reaction is based on a biological revulsion, rather than a learned cultural fear. In a 2013 article in Psychological Science, Wilkins and Cole write that the reaction is based on a brain response that associates the shapes with danger. Shapes that elicit a reaction were said to include clustered holes in innocuous contexts such as fruit and bubbles, and in contexts associated with danger, such as holes made by insects and holes in wounds and diseased tissue. Upon seeing these shapes, some people said they shuddered, felt their skin crawl, experienced panic attacks, sweated, palpitated, and felt nauseated or itchy. Some said the holes seemed "disgusting and gross" or that "something might be living inside those holes". Psychiatrist Carol Mathews believes that the responses are more likely from priming and conditioning.
A website, trypophobia.com, describes the phenomenon with videos and images. Images containing clusters of holes are presented in an arrangement that claims to rank the likelihood they will induce fear. Early images in the series include fruits such as oranges and pomegranates. Then, clusters of holes with a possible association with danger are presented, such as honeycombs, frogs, and insects and arachnids. Finally, images feature wounds and diseases. Using data from the site, Wilkins and Cole analyzed example images and believe that the images had "unique characteristics". They state that the reaction behind the phobia was an "unconscious reflex reaction" based on a "primitive portion of the brain that associates the image with something dangerous". In another research article, Le, Cole and Wilkins developed a symptom questionnaire that they say can be used to identify trypophobia.