Redback Spider Bite: Symptoms, First Aid Treatment & When to Call 000

Updated March 2026 · Reviewed by IRFA paramedic trainers · RTO 32154

Quick answer: A redback spider bite causes increasing pain at the bite site, sometimes progressing to sweating, nausea, muscle pain, and — in rare cases — systemic envenomation requiring antivenom. Apply a cold compress (not pressure immobilisation), keep the patient calm, and call 000 or Poisons Information Centre (13 11 26) if symptoms spread beyond the bite site. No Australian has died from a confirmed redback bite since antivenom became available in 1956.

How to identify a redback spider

The redback spider (Latrodectus hasselti) is one of Australia’s most recognisable and medically significant spiders. Females are the ones that bite — males are too small to penetrate human skin.

Female redback identification:

Body length: approximately 10 mm (body only, not including legs)
Colour: black with a distinctive red or orange stripe on the upper abdomen
Underside: red hourglass-shaped marking (similar to the American black widow, to which redbacks are related)
Web: messy, tangled web with sticky catching threads extending to the ground — usually in sheltered, dry locations

Where they live: Redbacks are found across all of Australia, in both urban and rural environments. They favour dark, sheltered spots: under outdoor furniture, inside sheds and garages, around pot plants, in meter boxes, under outdoor toilet seats, inside stored shoes, and around building materials left outdoors. In Queensland, they are active year-round due to the warm climate.

Redback bite symptoms — mild to severe

Not every redback bite results in significant envenomation. The spider controls how much venom it injects — “dry bites” with minimal venom do occur. Symptom severity depends on the amount of venom injected, the patient’s size and health, and the bite location.

Mild symptoms (most common)

Immediate pain at the bite site — often described as sharp or burning
Localised swelling and redness
Small red mark at the bite point, sometimes with a white halo
Pain that gradually increases over 1–3 hours before plateauing

Moderate symptoms

Pain spreading from the bite site to the surrounding limb
Localised sweating around the bite area (a characteristic redback symptom)
Nausea and mild abdominal discomfort
General malaise and headache

Severe symptoms (systemic envenomation — seek emergency care)

Severe pain spreading beyond the bitten limb to the trunk, chest, or abdomen
Profuse regional or generalised sweating
Muscle pain and cramping, particularly in the abdomen and legs
Elevated heart rate and blood pressure
Nausea, vomiting, and abdominal pain
In rare cases: difficulty breathing, tremors, or collapse

Symptoms typically develop gradually over 1–3 hours. Unlike funnel-web bites (which escalate within minutes), redback envenomation progresses slowly — giving time to seek medical attention.

First aid treatment (step by step)

The Australian Resuscitation Council (ARC) and Poisons Information Centre recommend the following first aid for redback spider bites:

Keep the patient calm and still. Movement increases venom circulation. Sit or lie the patient down in a comfortable position.
Apply a cold compress or ice pack wrapped in a cloth to the bite site. This helps reduce pain and slow local venom spread. Apply for 15 minutes on, 15 minutes off.
Do NOT apply a pressure immobilisation bandage. This is the critical difference from funnel-web and snake bite first aid. Redback venom is slow-acting and a pressure bandage can increase pain without significantly slowing systemic absorption.
Note the time of the bite and observe for progression of symptoms.
If pain is significant, give over-the-counter pain relief (paracetamol) if available and appropriate.
Call Poisons Information Centre (13 11 26) for advice on whether hospital attendance is needed, or call 000 if symptoms are severe or involve a child.
If the spider has been captured safely (e.g. in a container), bring it to hospital for identification. Do not attempt to capture the spider if it creates additional risk.

What NOT to do

Do NOT apply a pressure immobilisation bandage — this is for funnel-web spiders and snakes, not redbacks
Do NOT cut the wound or attempt to suck out venom — this is ineffective and creates infection risk
Do NOT apply a tourniquet — this can cause tissue damage and does not help
Do NOT use heat (hot water, hot compresses) — some outdated advice recommends heat for redback bites, but this is not supported by current clinical evidence and may worsen inflammation
Do NOT ignore spreading symptoms — if pain moves beyond the bite site, medical assessment is warranted

When to call 000

Call Triple Zero (000) immediately if:

The patient is a child under 8 years old
The patient develops severe pain, profuse sweating, or muscle cramping
There are signs of anaphylaxis (difficulty breathing, swelling of face/throat, collapse)
The patient has a known allergy to spider venom
The patient is elderly, pregnant, or has significant health conditions
You are unsure whether the spider was a redback or a funnel-web

If in doubt about the severity, call the Poisons Information Centre on 13 11 26 for expert clinical advice. They can assess symptoms over the phone and advise whether hospital attendance is required.

Redback bites in children

Children are at higher risk of significant envenomation because their smaller body mass means a proportionally larger dose of venom per kilogram. All redback bites in children under 8 should be treated as potentially serious.

Young children may not be able to describe their symptoms clearly. Watch for:

Unexplained crying or irritability
Reluctance to use the bitten limb
Sweating localised to one area (a key redback indicator in children)
Vomiting or abdominal pain without obvious cause

If a child has been bitten or you suspect a redback bite, take them to the nearest emergency department or call 000.

Antivenom — what happens at hospital

Redback spider antivenom has been available in Australia since 1956. It is the most commonly used antivenom in the country, with approximately 300–400 doses administered annually. Hospital treatment typically involves:

Pain assessment — monitoring symptom progression to determine whether antivenom is warranted
Antivenom administration — given intramuscularly or (less commonly) intravenously if systemic envenomation is confirmed. Most patients respond within 1–3 hours.
Observation — patients are typically observed for 2–6 hours post-treatment before discharge
Pain management — additional analgesia as required

Not all redback bites require antivenom. Many patients are observed, given pain relief, and discharged without antivenom if symptoms remain localised.

Redback vs other Australian spider bites

It is important to distinguish redback bites from other spider bites because the first aid treatment differs:

Redback — cold compress, no pressure bandage, slow symptom onset (hours). Antivenom available.
Funnel-web — pressure immobilisation bandage immediately, call 000 urgently, rapid symptom onset (minutes). Antivenom available.
White-tailed spider — ice pack, clean the wound, monitor for infection. No antivenom needed.
Wolf spider — ice pack, clean wound. Mild local pain only. No systemic effects.
Huntsman spider — ice pack, clean wound. Painful but not medically significant.

If you’re not sure which spider caused the bite, treat it as potentially serious: apply a cold compress (not pressure bandage), keep the patient calm, and call 13 11 26 for advice.

Prevention — reducing redback encounters

Redbacks prefer dark, sheltered locations and are rarely aggressive — most bites occur when the spider is accidentally disturbed or trapped against skin. Prevention measures include:

Shake out shoes, gloves, and clothing left outdoors before wearing them
Wear gloves when moving pot plants, stored building materials, or outdoor furniture
Check under outdoor chairs, tables, and play equipment before use
Clear webs from around doorframes, meter boxes, garden sheds, and outdoor toilets
Teach children to avoid reaching into dark spaces and to report spider sightings
Keep outdoor areas tidy — reduce clutter that provides shelter for web-building
Consider professional pest control if redbacks are established around your property

Redbacks in Queensland — where you’ll find them

Redback spiders are common across all of Queensland, from the coast to inland regions. They are particularly prevalent in:

Urban gardens and sheds — suburban properties across Brisbane, Moreton Bay, and the Sunshine Coast
Outdoor seating areas — under chairs and tables at cafes, beer gardens, and waterfront venues
Childcare centre play areas — outdoor equipment, sandpits, and garden borders require regular inspection
Construction sites — stored materials, temporary structures, and portable toilets
Rural properties — farm sheds, machinery, fence posts, and outdoor toilet blocks around Caboolture, Wamuran, and the Moreton Bay hinterland
Industrial estates — warehouses and loading docks in areas like Brendale, Virginia, and Narangba

Queensland’s warm climate means redbacks are active year-round — unlike southern states where activity reduces in winter. This makes ongoing awareness and regular property inspections important.

Learn proper first aid for spider bites and other emergencies

Knowing the correct first aid for spider bites — including the critical distinction between redback treatment (cold compress, no pressure bandage) and funnel-web treatment (pressure immobilisation bandage immediately) — is covered in our HLTAID011 Provide First Aid course. Our paramedic instructors teach you to identify and respond to venomous bites using scenarios drawn from real Queensland cases.

IRFA delivers first aid training across Queensland:

Sippy Downs — our headquarters, from $90
Caboolture — ideal for rural Moreton Bay residents who encounter redbacks on properties
North Lakes — for families in North Lakes’ new residential estates
Redcliffe — peninsula families and outdoor workers
Virginia/Northgate — industrial estate workers who encounter redbacks in warehouses and loading docks

$95, 4 hours, same-day certificate. Book HLTAID011 now → or call 1300 766 298.