Jan. 1, 2010 -- People who get the shivers over tarantulas likely imagine a gigantic bite from a fanged mouth. But as one man recently found out in England, tarantulas are more likely to defend themselves by shooting a mist of microscopic barbed hairs straight into your eye.
At first, doctors were perplexed when the 29-year-old man came into their ophthalmologist's office at the St. James University Hospital in Leeds. The man didn't mention a run in with his pet tarantula.
"The patient came in with a red eye… and he already had a working diagnosis of conjunctivitis," said Dr. Zia Carrim, co-author of the case report who declined to identify the patient.
His eyes had been red and painful for three weeks, yet the usual rounds of medication for conjunctivitis (pink eye) had done nothing.
By the time he got to St. James, he was photophobic, meaning light hurt his eyes. Luckily Carrim's colleague, Dr. Jonathan Norris, decided to look at the patient with the highest magnification possible.
"He [Norris] was really surprised… when you had high magnification, he saw these tiny little protruding spots," said Carrim. "He said, 'I think this is really strange. I see really small hairs in your eye. I don't know what it is."
Finally, the patient remembered a strange incident while cleaning out the cage of his Chilean Rose tarantula.
"While his attention was focused on a stubborn stain, he sensed movement in the terrarium. He turned his head and found that the tarantula, which was in close proximity, had released 'a mist of hairs' which hit his eyes and face," wrote Carrim in the case report.
The man had no idea that those hairs were armed with barbs, which could help them penetrate into his eyes. Some barbs had already made it past his cornea, past his iris and to the back of the eye, called the retina.
Carrim said it would take a week after an attack for a person to feel symptoms. As the tiny hairs work their way into the eye with every blink, eventually the eye becomes painfully inflamed.
To make matters worse, the hairs were so small, doctors could not surgically remove them, so Carrim and his colleagues treated the patient with a round of steroids to flush them out.
Tarantula's Hair Flicking Habit Relatively Unknown
Neither Carrim nor the patient knew that some tarantulas kick off urticating hairs when they are frightened.
Unfortunately, many pet shops do not tell owners, according to Cindy Steinle, who has adopted out more than 30 tarantulas in her Small Scale Reptile Rescue in Milwaukee, Wis.
"It's a defense technique. They [the hairs] are basically akin to little pieces of fiberglass," said Steinle, who noted rubbing hairs off the abdomen is often a tarantula's first line of defense, rather than biting.
Steinle says she keeps herself and her three pet tarantulas safe when cleaning her cages by putting a cup over the spiders. She never handles them and has never seen a tarantula shoot urticating hairs in her four years as a tarantula owner.
To learn more tips on caring for a tarantula, Steinle recommends a lot of research and visiting an online community such as insecthobbyist.com.
In her experience rescuing pets, she found many neighborhood pet stores do not always give out the best advice for exotic pets.
"Pet shops usually don't have a vast array of knowledge unless they are a specialty shop," she said.
Indeed, Dr. Roberto Pineda, director of refractive surgery at the Massachusetts Eye and Ear Infirmary in Boston, says some of those who are most at risk are pet store employees.
"Usually, they're very similar to this story where they've seen a tarantula, and were cleaning a cage and felt something," said Pineda, who has treated just two incidents in the last 18 years.
In both cases, the person didn't know the tarantula could spray barbed hairs, in both incidents the person didn't feel symptoms for a week and in both incidents the person didn't realize the spider was to blame for their red eyes.
Tarantula's Barbed Hairs Could Cause Vision Loss
"What's nice for us as ophthalmologists is that we can see these fine filaments in the cornea, so if you've seen this before, or heard of it, you can treat it," said Pineda. "But most eye care specialists aren't aware of this condition."
His colleague at Massachusetts Eye and Ear Infirmary agreed.
"If you've picked five or six ophthalmologists off the street and asked them if you've ever seen a problem with a tarantula, they'd say 'no,'" said Dr. Ankoor Shah, director of the eye trauma service at Massachusetts Eye and Ear Infirmary.
Without treatment from experts like Shah, Pineda or Carrim, victims of a tarantula's barbed hair could eventually face severe scarring and vision loss.
Shah said hairs stuck in the outer part of the eye can cause scarring to the cornea. If the hairs migrate into the area between the cornea and the iris (the colored part of the eye) Shah said the inflammatory reaction can cause pain, light sensitivity and can even create enough pressure in the eye to cause damage to the optic nerve. If left untreated, barbs in that area of the eye could cause scarring and cataracts.
Shah said the case of the 29-year-old British man was particularly severe.
"Somehow, one of these hairs got all the way to the back of the eye... and that can cause problems with the retina."
Despite the young man's brush with danger, Carrim said he didn't seem too angry with the tarantula.
"Even after he realized it was the tarantula who had done this, he was still keen to hang on to it," said Carrim.