WARNING: Potentially graphic images
Have you ever looked at an image of a beehive, pockmarked skin or perhaps a lotus seed head and suddenly felt anxious and ill?
Your heart races. You feel nauseous and breathless. And your skin starts itching. Well my friend, you could be trypophobic [pronounced: TRIP-OH-PHOBIC].
Trypophobia - an intense or irrational fear of clusters of bumps or holes — was first described on the internet in 2005. Although it may sound wacky at first, the phobia is believed to affect up to 20 per cent of the population.
Italian computer scientist and musician Paola Barra, 26, recalls the first time she had a visceral reaction to a pattern of holes. She was just 12 years old.
"There was an irregular ditch and it was filled with little stones and little holes, and I couldn't look at it without feeling deep discomfort," she says.
Over time, Paola realised that this wasn't just a once-off experience.
"The same happened to me with sunflowers or caviar. I soon began to collect these kinds of images on my computer," Paola says.
Whenever she viewed these photos, Paola would experience "an incredible itchiness in my fingers".
For eight years, Paola had no idea why this occurred. Then one day, she did an internet search for the music genre "trip hop". Serendipitously, the search engine threw up the word "trypophobia".
Paola was amazed to discover this was her phobia. Not long afterwards, she started a Facebook group with the aim of "informing people about the existence of trypophobia".
The trypophobia Facebook page currently has nearly 6000 followers around the globe. While Paola admits she is "surprised at the success of the page," it leads her to believe "trypophobia is more common than we think".
She says followers often write to her and describe their own physical and mental responses to trypophobic images.
"The most common annoyances are itching, anxiety, nausea and sometimes vomiting," she says.
Some of Paola's fans are unimpressed that she actually posts photos that trigger their phobia.
"Others have thanked me because I have publicised the existence of trypophobia and previously, they believed themselves to be the only ones [with it]," she says.
While trypophobia is not yet recognised as a medical diagnosis, it is gaining traction among some experts.
For more than 40 years Arnold Wilkins, Emeritus Professor of Psychology at the University of Essex in the United Kingdom, has studied the severe responses some people have to repetitive patterns.
The first patient Dr Wilkins ever saw with this issue was when he was studying in the Canadian city of Montreal in the early 1970s.
"I was asked to see a patient who had seizures when she looked at striped lines, which at the time was thought to be extremely rare," he says.
After spending decades investigating aversive patterns, he now believes the opposite is true; a negative physical response to certain types of patterns is not rare.
"I would say about at least 10 to 20 per cent of the population is affected to some extent by aversive patterns," Dr Wilkins says.
More recently Dr Wilkins and PhD student An Trong Dinh Le, have been investigating trypophobia.
Dr Wilkins explains that a so-called "Fourier analysis" of aversive patterns — whether they are stripes or holes — shows they all have similar mathematical properties.
"So although they're very different patterns, they may be having similar effects on the visual system," Dr Wilkins says.
He goes on to explain that looking at something that's uncomfortable causes greater "oxygenation of the visual part of the brain."
And because your brain is working harder than usual, Dr Wilkins says this may in turn lead to "overloading the visual system."
He has "a hunch" that trypophobia has an evolutionary element.
"The trypophobic images have the same characteristics as the markings on poisonous animals.
"[So] there might be some fairly fundamental fear involved in these kind of markings," he says.
He points to the striped patterns on wasps and snakes and even trypophobic human skin lesions as "very useful to avoid".
But does trypophobia have a learned element to it?
Just like with Paola's experience, Dr Wilkins says many trypophobics "can remember a particular instance when it started. And so a phobia built from that initial episode".
In Dr Wilkins' view, the internet has created a kind of "bottom-up medicine" because people from all over the world are now able to connect with others that share their symptoms.
"Trypophobia is just one example of several other symptom clusters that have been recognised by sufferers," he says.
However Dr Wilkins stresses that even though trypophobia has only recently come to light, the condition has been around for a long time. He says the internet isn't to blame for its existence.
"I've come across patients who've had it all their lives, and these people are in their 60s," he says.
For Paola's part, she has grown almost immune to trypophobic images because managing her Facebook page has "forced me to get used to [them]."
There is one exception, though.
"The one thing that continues to bother me is the video of the Surinam toad who gives birth out of holes in its back. I want to squeeze it and let out all the little frogs out," she says.