The Redback Spider Bite: Are Some People Immune?

A couple months ago I did an interview with Professor Julian White (MB, BS, MD, FACTM), Consultant Clinical Toxinologist and Head of Toxinology at the Women’s & Children’s Hospital, Adelaide. We discussed Redback Spider Antivenom Doesn’t Work; True or False?

As some of you will know, I was bitten by redback spider and when I telephoned my doctor I was told not to panic, only a small minority of bites cause a reaction that needs medical intervention.

Spider, Australian Red-back,  female spiderIn my case I was lucky, I suffered no adverse reactions and by the next day it was as if it had never happened. Any of you who have read my post What It’s Really Like to Be Bitten by a Redback Spider and in particular all the comments below it will know that for many people the reactions can be quite severe.

After I’d finished my interview with Professor White, quite a while after, I found myself kicking myself, not literally though, that would be silly. I hadn’t asked one of the most important questions of all, a question that has also been debated in the comments without ever reaching a definitive conclusion.

I really needed to get back to Julian but that wasn’t easy, I had been speaking to him through a media agency and he’s a busy man. Fortunately I know Geoff Coombe, my snake expert and he knows Julian, they’ve worked together. I asked Geoff, Geoff asked Julian, and Bobs your uncle. Here’s the answer, but first…

What is the Question?

Are some people naturally more inclined to react to a redback spider bite whilst others show less of a reaction simply because of biology, or is the reaction caused by a redback spider bite directly related to the amount of venom injected by the spider?

You know how some people are allergic to wasp stings? Are some people simply allergic to the redback spider and for everyone else it is just painful and then it goes away?

So, is it the amount of venom, or the person?

Over to Professor Julian White for this most comprehensive answer:

Professor Julian White

Professor Julian White

“A number of factors affect how a particular person reacts to a red back spider bite;

  • how big was the spider and what sex?;
  • how much venom was injected?;
  • what variability was there in the venom content on that day, from that spider?;
  • how large/old was the patient?;
  • what pre-existing diseases did the patient have, if any?;
  • what first aid was used?

While allergy to spider venom is possible, evidence currently available indicates it most likely plays a very small role, or no role at all, in spiderbite, in contrast to insect stings where it is a significant problem.

The factors mentioned above mean that there is a wide spectrum of severity for red back spider bites, from minimal effect to severe effects, and while patient factors can influence this, it seems likely that the most important factors, in most cases, are spider-related, except perhaps for the size of the patient. A small child is more likely to have more severe envenoming, simply because of the body mass versus venom mass equation; a smaller body mass means a higher dose of venom per kg, for a given amount of venom injected.

Are some people inherently more susceptible to the effects of red back spider venom?

There is no clear answer to this question, but theoretically it is possible that some people have subtle differences in receptor proteins on nerve cells that either enhance or reduce effectiveness of venom, but whether this plays a role in envenoming of humans by these spiders is speculative, not currently answerable with clear evidence.

What is clear to clinicians treating cases of significant red back spider envenoming is that in most cases specific antivenom appears to be the most effective treatment.” – Professor Julian White


So there we have it, the definitive answer. For some time I believed that maybe I was one of the lucky ones, my redback spider bite caused me very few problems, I thought maybe I was immune.

Then as more comments appeared on my original post I became unsure whether I really was a lucky one or not.

Now I do know for sure, I’m not one of the lucky ones; it’s much more likely that some other factor meant that I didn’t suffer as many others have.


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{ 8 comments… add one }
  • Paul February 16, 2022, 6:46 pm |

    I’ve had 3 red back bites and only 1 had an adverse reaction.
    Much worse was the Western Brown Snake that bit me when I stuck my hand in the pool filter basket, where the snake had decided to cool off, to clean out the leaves.

    • BobinOz February 21, 2022, 9:38 pm |

      Three redback bites plus a brown snake bite? You have had some fun, haven’t you? I hope you don’t go swimming in the sea too often 🙂

      I have another page on this site about redback spider bites…
      …got quite a few comments, and some people suffer enormous pain that lasts for years after a redback spider bite, and others just get almost nothing. Every bite is different.

  • Jackie Clifton January 13, 2017, 12:59 pm |

    Yes, I also got bitten by a redback. The pain is really intense, burning and excr uciating! In my case the hospital put a half plaster cast to my wrist to stop movement. They only gave me pain killers, but they did know it was a redback. The pain lasted about two weeks, then gradually subsided. My pain level is high and I did cope with it, JUST!!!!! I wouldn’t recommend being bitten!

    • BobinOz January 13, 2017, 4:56 pm |

      Yes, it’s quite incredible how such a small spider can cause such an immense amount of pain in much larger humans. For sure, getting bitten is not recommended. Glad to hear you have recovered.

  • Bronwyn January 12, 2017, 2:27 pm |

    Hi. Was just talking about my redback bite this am and thought I would look on Google. Found this site. My bite was definitely a redback. I experienced a pain ( cross between broken bone ache and burning) about a minute after donning shoes one day. Inside the shoe was a large live redback. While I did not feel the bite (3) there were 3 tiny dots in the webbing between two of my toes ( and the origin of the pain). This rapidly worsened and spread upward. That night at one point I would gladly have had my foot amputated so intense was the pain.. Despite pain up to my groin and profuse sweating in emergency I was not given anti-venene. In fact they practically ignored me. Initially I had to plead for attention because of the pain although I had already handed over the story and the spider. The doctor told me “50percent of people die from this” then left to answer her mobile. 30 muins later I asked if I would e amoungst the living and she said ” we will have to wait and see”. I asked what could happen, told I could go into sudden respiratory arrest so needed to be observed 4 hours. Then stuck me in a an enclosed private waiting area where they were unable to see or hear me. When I asked what to expect (on being allowed to leave 2 hrs later) they told me to google redback bites. Then a thoughtful nurse said she had only seen one bite before. Apparently the man was found at 4am running naked in the streets because his pain was out of control. She said he ended up in ICU intubated but couldn’t recall any more detail. Reassuring?? They thought ice was enough for my pain. Wrong!
    ( and I do have a high pain tolerance) While the intensity died down over the following day the pain did remain for several weeks. In my case… Big spider, three (known at least) bites and in a thin skinned area which is more readily penetrated. Dont’ want that ever again. The following year on the same day I went to put the same shoe on that same foot but something told me ‘no’. I checked , and guess what??? Yep… there was a redback. Out went those cream coloured croks…

    • BobinOz January 12, 2017, 9:47 pm |

      Well, this is intriguing. I have another post on this same subject, it’s been going since 2010 and has hundreds of comments and some are stories of people who have been bitten by a redback.

      You can see the whole post here…

      But what is interesting is just a couple of days ago I had a comment, look for one from Jodie January 11, 2017, 9:33 am. Her daughter was bitten by a redback and ended up in intensive care but before that also received some quite indifferent treatment from the hospital.

      I find this quite shocking and a little strange, and I find it especially weird that you were told that 50% of people die from this. Up until last year Australia could proudly claim that nobody had died from a spider bite in this country since 1979 and that time I think it was a funnel-web. That claim has now been clouded with the death that may have been caused by a redback spider, but as far as I am aware has not yet been confirmed to be the case by the coroners.

      If it is confirmed though, it will be the first recorded death from a redback spider in Australia since 1955. That doesn’t sound like 50% of people dying to me.

      I really don’t know what was going through the minds of the people working at the hospital, but I’m pleased to hear that you have made a full recovery now. Careful with those crocs 🙂

  • Jackie Clifton April 10, 2016, 10:49 pm |

    Quite enlightening. I was bitten 5 days ago, received no anti venom at the hospital, but am still in a lot of pain. Was it a redback? I still have the burning pain and ice makes it worse!

    • BobinOz April 11, 2016, 8:23 pm |

      Hmm, it’s difficult to say Jackie, if you visit my post called ‘What’s it really like to be bitten by a redback spider’, there is a link to it in the above article, you will read hundreds of comments from people who have also been bitten by these critters.

      It may help you identify whether it was a redback or not, some people have reported experiencing pain for quite some time. Have a read and feel free to ask for advice in the comments on that page as well if you wish. Cheers, Bob

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