Trypophobia^[1] is a claimed pathological fear of objects with irregular patterns of holes. Thousands of people claim to have the condition,^[2] but it is not recognized in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM) or other scientific literature.^[3][2] The term was coined in 2005 from the Greek τρύπα (trýpa) "hole" and φόβος (phóbos) "fear".^[3]

British academics Arnold Wilkins and Geoff Cole, who claim to be the first to scientifically investigate trypophobia, believe the reaction to be based on a biological revulsion, rather than a learned cultural fear.^[2] In a research article they wrote for Psychological Science, Wilkins and Cole write that the reaction is based on a brain response that associates the shapes with danger. The type of shapes that elicit a reaction were stated to include clustered holes in skin, meat, wood, soil, plants, wounds and bubbles, and that upon seeing these shapes, some people said they felt their skin was crawling, shudder, feel itchy, experience panic attacks, sweat, palpitate and feel nauseous. Some said the holes seemed "disgusting and gross" or that "something might be living inside those holes".^[4][5]

Using data and information from Trypophobia.com, Wilkins and Cole analyzed example images and believe that the images had "unique characteristics".^[6] Wilkins and Cole 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".^[4][7] In another research article, Le, Cole and Wilkins developed a symptom questionnaire which they state can be used to identify trypophobia. ^[8]