“Man loses both legs and arms at risk after white-tail spider bite,” trumpeted a headline in the Daily Telegraph last week.

“White-tail spiders are commonly found in homes across the country, usually hiding in bedding and clothes draws [sic],” the newspaper went on, warning the spider’s bites “cause ‘necrotising arachnidism’, which is basically ulcerating skin loss”.*

As a certified arachnophobe, I’m happy to believe the worst of spiders, but really?

The myth of the flesh-eating white-tailed spider was exploded more than a decade ago by this prospective study, published in the MJA.

Researchers from the University of Newcastle studied 130 cases of confirmed white-tailed spider bites. All of the arachnid’s victims experienced some level of pain or discomfort from the bite, with less common effects including skin redness and itch.

How many suffered necrotic skin lesions? Zero, that’s how many.

Yet, the myth lives on. And not just in Australia or in relation to this particular, fairly inoffensive, spider.

US entomologist Dr Richard Vetter has written of similarly unsubstantiated claims about necrotic wounds caused by his country’s brown recluse spider, for example.

In some parts of the world, spiders are apparently venerated but, in the West at least, their association with disease goes back a long way.

Lead author of the 2003 MJA study, Professor Geoffrey Isbister, has traced the scapespidering back to medieval times, when the eight-legged creatures were blamed for spreading the Great Plague.

“The association with plague is thought to result from the fear of a disease of unknown cause and the need to attribute the disease to an external agent,” he wrote in the Lancet.

Because arachnids were seen as a plausible cause, “fear of disease manifested as anxiety and hysteria about spiders”.

Even more fanciful was the epidemic of “tarantism” that spread across southern Europe from the 15th to the 17th centuries and, according to Professor Isbister, is still occasionally diagnosed in the region today.

Allegedly caused by the bite of a tarantula, the condition brought with it sweating, pain, tremors, rigors and sometimes “madness”.

The only cure was to dance energetically for 3–4 days, a treatment enthusiastically embraced by residents of the southern Italian town of Taranto, where the disease originated.

They established dancing festivals, writes Professor Isbister, using tarantism as “an opportunity to resurrect orgies and attribute their unseemly behaviour to spider bites”.

I’m not aware it has led to orgies, but another myth exposed by Professor Isbister is the widespread belief that daddy longlegs are actually the most venomous of all spiders, “despite no reported bites and the venom never having been studied”.

That’s not just a Western urban myth. I was even told it when I was trekking through the jungles of Borneo, by a local guide eager to impress foreign visitors with the many dangers of his rainforest.

Spiders are pretty much always with us, and many of us fear them (it’s the scuttling legs!), so perhaps it’s not surprising they have so often been credited with superarachnid powers.

But, in most cases of spider bite, the perpetrator is not captured or identified by an expert, meaning that any alleged causal connection is pretty much conjecture.

And when even clinicians buy into the myths, it may put patients at risk.

As Professor Isbister makes clear, misdiagnosis of necrotising arachnidism may lead to failure to treat a condition that is actually there, such as basal cell carcinoma or various bacterial or fungal infections.

It’s clearly time for a more evidence-based approach to our eight-legged friends.

Apart from huntsmen, that is. I’d believe anything of them.

* The Daily Telegraph article and others were later modified to incorporate the views of experts questioning the spider’s role in this tragic Victorian case.

Jane McCredie is a Sydney-based health and science writer.

 

To find a doctor, or a job, to use GP Desktop and Doctors Health, book and track your CPD, and buy textbooks and guidelines, visit doctorportal.

 

 


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4 thoughts on “The myth of the white-tailed spider

  1. Dr. Gabrielle McMullin says:

    I frequently see patients with leg ulcers or cellulitis that is attributed to spider bites …..and that is never the case. The problem is invariably uncontrolled oedema of the limbs from a variety of problems – heart failure, pulmonary oedema, obesity or venous insufficiency. Once bacteria get into the interstitial tissue they cannot be targeted by intravenous antibiotics and so overwhelming sepsis occurs with inherent drop in blood pressure which leads to the over use of inotropes which then leads to limb loss. Getting control of the oedema is the key to the problem

  2. Mark Walland says:

    Don’t underestimate daddy-long legs: could be venom, could be innards, but produces a nasty keratitis which can strip the corneal epithelium. Commonly after being inadvertently squished while rubbing the eye in bed at night.

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1324603/pdf/brjopthal01122-0059.pdf

  3. Dr David Long says:

    This was such a fantastic article and gave me and my colleagues a great belly-laugh! It was originally attributed to The Stawell Times.
    The second paragraph stated that the man didn’t even realise he had been bitten by a spider until his leg became red!!! The “expert” quoted was a local pest exterminator, who warned everyone that white-tails are dangerous and ubiquitous. Call me..
    To their credit, in the last part of the article Fairfax did have comments at odds to the headlines and the first half of the article.
    It still gives me a chuckle…

  4. Ian Hargreaves says:

    One of my school holiday activities was volunteer work at the Australian Museum, including working with Mike Gray, the arachnologist who co-authored the debunking paper about white tails referred to above. On my second day as an intern, the only after-hours casualty cover at a peripheral hospital, I was called urgently to casualty to see a funnel web spider bite. I ran down in terror, going through the options of a difficult intubation with haemorrhagic pulmonary oedema, and how to do advanced life support while struggling to get even the most basic drip in.

    On arrival there was no obvious wound on the lady’s foot, but her adult sons were proudly brandishing the offending creature in a jar. Seeing a juvenile male wolf spider, my inner calm was completely restored. However, convincing the family that there was probably no bite, and even if there was, it was not harmful, was as difficult as the resuscitation would have been!

    I have witnessed a Huntsman bite, as my tent-mate crawled into his sleeping bag, and then exited same sleeping bag, cursing and flailing. A large Isopeda sp. (gender indeterminate) flew past me and out the door of the tent. The abdominal bite marks looked like snake fangmarks, large enough to draw blood, producing a local erythematous reaction around a centimetre in diameter. I am reliably informed that it felt something like a bee sting or bull ant bite (with added points for surprise).

    No necrotism followed, nor any Spiderman powers. But the ability of an araneomorph (sideways-biting fang) spider to bite a human abdomen would lead a reasonable casualty doctor to presume the bite was a mygalomorph (downward biting) funnel web. Rest assured, Jane – just don’t sleep with a huntsman.

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