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Spider Bite – Identify & Treat

Australia is home to some of the world’s most venomous spiders.

Don’t waste time if you are bitten by a spider. Contact a doctor or visit a medical facility and get proper treatment.

Severe allergy or anaphylactic shock can be triggered by even the most harmless of spider bites. It would be foolish to ignore the fact that spider bites can have more serious consequences.

A spider bite can be fatal not because — or not only because — of the toxicity of the venom, but because anaphylaxis causes swelling and obstruction of a person’s airways, depriving them of oxygen.

Spider bite symptoms vary depending on the species of the offending arachnid. Affected individuals can experience symptoms that include:

  • Pain, swelling at the bite site
  • Profuse sweating
  • Abdominal or generalised pain
  • Involuntary muscle contractions
  • Headache
  • Chills, fever, weakness
  • Unconsciousness

Spider bite first aid should be administered until medical professionals can take over. But, in some cases, first aid can only do so much.

Serious envenomation and anaphylactic shock are medical emergencies. 

Symptoms of anaphylaxis include:

  • Development of rashes, hives, itchiness
  • Stomach cramps
  • Swelling of the mouth, throat, face
  • Wheezing, difficulty breathing

Emergency hospital treatment, in these cases, is a necessity.

Thanks largely to all the work that has gone into anti-venoms, we’ve had no deaths from spider bites in Australia since 1981.

Why do spiders bite people?

Spiders will not go out of their way to bite you. They’re not usually aggressive and clearly you are not their food.

A bite would be a defence response when a person unwittingly brushes up too close, or tries to capture the spider.

Top 10 most dangerous spiders in Australia

  1. Sydney Funnel Web Spider
  2. Other Funnel Web Spiders
  3. Redback Spider
  4. Mouse Spider
  5. Trap Door Spider
  6. White Tailed Spider
  7. Australian Tarantula Spider
  8. Recluse Spider
  9. Huntsman Spider
  10. Common Garden Orb Spider
Australia's top 10 most venomous spiders

Download this chart as a PDF


1. Sydney Funnel-Web

Danger Level: High

The Sydney Funnel-Web spider is, without doubt, the most dangerous spider in Australia. It is also a candidate for one of the most dangerous spiders in the whole world.

One in 6 bites from a Sydney Funnel-Web spider causes a severe reaction. Anti-venom is available when you seek emergency medical treatment from your local general practitioner or hospital.

Distribution: New South Wales, particularly in forests and urban areas. Sydney Funnel-Web spiders have been found in backyards and swimming pools and can be quite aggressive when they feel threatened.

Identification:

  • 5-3.5 cm in size
  • Black to blue-black colour
  • Shiny appearance
  • Large, powerful fangs
  • Hairless, shiny head

Behaviour: Sydney Funnel-Web spiders are aggressive when threatened

Appearance:

Sydney Funnel Web Spider

Image source: www.willkillpestcontrol.com.au/spiders-pest-control.php


2. Other Funnel-Webs

Danger: High

Among the 40 species in Australia, only 6 species of funnel-webs can cause severe envenomation. They are most active during the warmer months of November through March.

Distribution: Most common in Southern Queensland and Northern New South Wales.

Identification:

  • 1-5 cm in size
  • Colour ranges from black to blue-black to plum to brown
  • Hairless shiny head

Behaviour: Funnel-web spiders are aggressive when threatened.

Appearance:

other_funnel_web_spider

Image source: www.museumsvictoria.com.au


3. Redback Spider

Danger Level: High

The Redback spider may be life-threatening to a child, but it is rarely serious for an adult. There are approximately 2000 recorded Redback spider bites each year, and about 250 of the affected individuals receive anti-venom. No deaths due to Redback spider bites have been recorded since the anti-venom was introduced in the 1950s. The main symptom of a Redback spider bite is severe and persistent pain.

Distribution: Many habitats throughout Australia, including urban areas. They often try to hide in dry, sheltered places such as garden sheds, mailboxes, and under toilet seats.

Identification:

  • Female is more dangerous than the male. She is approximately 1 cm, with a distinct red stripe on its abdomen.
  • Male Redback is approximately 3–4 mm and light-brown in colour. The males have white markings on the upper side of the abdomen and a pale hourglass marking underneath.

Behaviour: Redback spiders are nocturnal and only the female bite is dangerous.

Appearance:

size_redback

4. Mouse Spider  

Danger Level: Medium

There are 8 species of Mouse spider, all found in and around Australia. However, only one case of severe envenomation has been reported. Funnel-Web spider anti-venom is found to be effective on Mouse spider bites, as the two bites are similar and are treated with similar caution.

Distribution: Throughout Australia. Found normally in burrows, near waterways and occasionally in suburban areas. The burrows feature 2 surface trapdoors, almost at right angles to each other. These silk and soil trapdoors are well-camouflaged and the 2 doors make for an ingenious trap.

Identification:

  • Bulbous head and jaw
  • Smooth and shiny head and legs
  • Males sometimes have colour markings on the head

Behaviour: Mouse spiders are typically lethargic and rarely aggressive. They prefer to be active during the day.

Appearance:

mouse_spider_maleWeb
Male and female Mouse Spider. Image source: Australian Museum


5. Trap Door Spiders

Danger Level: Medium

Trap Door spiders only cause minor symptoms such as localised pain. However, their venom can also sometimes cause nausea, lethargy, and malaise. Trap Door spider bites are similar to a Funnel-Web spider bite and are therefore treated with similar caution.

Distribution: Trap Door spiders are found throughout Australia in natural and urban environments.

Identification:

  • 5 to 3 cm long
  • Females are significant larger than males
  • Males are more aggressive when threatened than females
  • Live in tunnels, often with circular shaped doors
  • Lifespan between 5-20 years

Behaviour: Aggressive when threatened.

Appearance:

trap_door_spider

6. White-Tailed Spiders

Danger level: Medium

Recent studies show that the venom of the white-tailed spider causes no major danger to humans and is limited to mild local pain.

Distribution: White-tailed spiders are found in natural and urban areas across Southern Australia, from Southern Queensland to Tasmania and from east to west coast of Australia.

Identification:

  • Whitish tip at end of abdomen
  • 2-1.8 cm in length, legs can span up to 2.8 cm across
  • Typically dark reddish to grey in colour, with dark orange-brown banded legs

Behaviour: White-tailed spiders are active and wander about at night, hunting other spiders.

Appearance:

White-tailed Spider


7. Australian Tarantulas

Danger Level: Medium

Australian Tarantulas are non-fatal to humans. However, they can render painful bites because of their large fangs. Nonetheless, effects such as vomiting and fever are very rare. Take note, however, that an Australian Tarantula bite can be fatal to dogs.

Distribution: Australian Tarantulas are found in Queensland, New South Wales, South Australia, and Western Australia. Some species can also be found as far south as Victoria.

Identification:

  • 6 cm body and up to 16 cm leg span
  • Large fangs (1 cm long)
  • Hairy
  • Dark or light brown, often with a silvery sheen

Behaviour: Their prey usually consists of insects, lizards and frogs, but they do occasionally prey on bird hatchlings. Australian Tarantulas are also known as whistling or barking spiders because some species are able to make sounds by rubbing their front limbs against their jaws.

Appearance:

Australian Tarantula


8. Recluse Spider

Danger Level: Medium

Recluse Spiders have potentially dangerous venom that can be haemotoxic and can damage the blood and skin. There has been no case of Recluse spider envenomation reported in Australia.

Distribution: Southern Australia.

Identification:

  • 6–20 mm
  • Ranges in colour from cream-coloured to dark brown or blackish grey

Behaviour: Recluse spiders are not inclined to bite.

Appearance:

Recluse Spider

9. Huntsman Spiders

Danger: Low

Huntsman spiders are reluctant to bite and will more likely run away when approached. Their venom isn’t considered dangerous to humans. The danger usually comes from the accidents they cause rather than their bite.

Distribution: Huntsman spiders are widespread throughout Australia.

Identification:

  • Up to 15 cm leg-span
  • Bristly
  • Dark to light brown, sometimes grey

Behaviour: Huntsman spiders are unlikely to bite and prefer to run away.

Appearance:

Huntsman Spider

10. Common Garden Orb Weaver Spider

Danger Level: Low

While the bite from a Common Garden Orb Weaver Spider can cause minor effects, such as local pain, they are aggressive and the most common species of spider to bite.

Distribution: Common throughout Australia.

Identification:

  • 5 cm and 3 cm
  • Stout
  • Reddish brown or grey
  • Roughly triangular abdomens, sometimes with a white or brown stripe
  • Two noticeable bumps towards front of abdomen

Behaviour: Common Garden Orb Weaver Spider are highly aggressive and likely to bite when disturbed. They are active at night and find a sheltered place to hide during the day, such as under leaves or in clothes on the washing line.

Appearance:

Garden Orb Spider

First aid for spider bites

Being able to identify the dangerous Australian spiders and knowing their behaviour will help you avoid the harm they could bring. But it’s also important you know what to do if one of these critters bites you or someone else.

The information that follows is pertinent but should not be taken as medical advice. A bite from one of these dangerous spiders needs prompt and proper attention. Please seek the closest emergency medical practitioner or hospital as soon as possible.

First aid for spider bites differs, depending on the species of spider. For example, a Redback spider bite will require a cold compress. A Funnel-web spider bites require pressure immobilisation bandaging to arrest venom circulation.

Reaction to a spider bite can also differ from person to person. The potential for a life threatening anaphylactic reaction cannot be discounted. Read our article What is Anaphylaxis? for more information about this condition.

In all cases, medical attention should be sought as soon as possible. 

Note: even for a spider that appears to have weak venom, you should follow similar precautions to treating a Funnel-web spider bite.

When does a spider bite become an emergency?

The Sydney Funnel-web spider, for example, is one of the most venomous spiders in the world. Their large chelicerae or fangs allow them to bite deep into the skin, delivering atracotoxin that is particularly dangerous to humans and other primates.

Envenomation & anaphylactic shock due to spider bites

For severe allergic reactions, the first aid administration of adrenaline or epinephrine using an auto-injector is advised.

A first aid responder should not hesitate to use the auto-injector immediately for anaphylaxis, followed by the Anaphylaxis Action Plan.

First Aid for Funnel-Web Spider Bite

Any bite from a large (greater than 2 cm) dark-coloured spider in parts of NSW or South-Eastern Queensland should be considered a possible bite from a Funnel-Web spider. Immediate emergency treatment should be given.

Signs and Symptoms:

  • Pain at the bite site
  • Tingling around the mouth
  • Profuse sweating
  • Copious secretions of saliva
  • Abdominal pain
  • Muscular twitching
  • Breathing difficulty
  • Confusion leading to unconsciousness

Treatment:

  • Keep the casualty at rest, reassured, and under observation.
  • Call 000/112.
  • Follow the basic life support guidelines (DRSABCD).
  • Apply Pressure Immobilisation Technique.
  • The purpose of the pressure immobilisation technique is to restrain movement of venom from the bite site into circulation, thus “buying time” for the patient to reach a medical facility. Apply a bandage over the bitten area as tightly as you would for a sprained ankle, and immobilise the limb. Extend the bandage up the limb. Only use the pressure immobilisation technique for Funnel-Web spider and snake bites.
  • Do not use a tourniquet.
  • Do not cut, suck, or wash the bite site.

First Aid for Redback Spider Bite

A Redback spider bite may be life-threatening to a child, but is rarely serious for an adult. However, you should take caution with all Redback spider bites.

Signs and Symptoms:

  • Onset pain delayed for 5 minutes than increases in intensity
  • Nausea and vomiting
  • Abdominal or generalised pain
  • Sweating
  • Restlessness
  • Palpitations
  • Weakness or muscle spasm
  • Fever

Treatment:

  • Keep casualty under constant observation.
  • Apply an ice pack or a cold compress on the bite area to lessen the pain.
  • If the casualty is a young child and collapse occurs or pain is severe, follow the basic life support flow chart.
  • Call 000/112 or transport the casualty to a medical facility as soon as possible.
  • Do not use a pressure immobilisation bandage.

First aid for other spider bites

For bites from large spiders (smaller than 2 cm) or from light-coloured spiders, follow the treatment as for a Redback spider bite.

Note: Even when a spider appears to have weak venom, you should follow similar precautions to treating a bite from a Funnel-Web spider. A spider bite reaction can differ from person to person, potentially leading to an anaphylactic reaction, which can be life threatening. Refer to our article  What is Anaphylaxis? for more information.

In all spider bite cases, seek medical assistance as soon as you can.

DisclaimerThis article is for informational purposes only. It does not constitute, replace, or qualify as any form of first aid training.


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