Spider bites

Most spiders in New Zealand are harmless, but the katipo, redback and white-tailed spiders can be harmful and should be avoided.

  • It’s rare for significant problems to result from a spider bite.
  • Always try to capture the spider and take it with you when you seek medical help.

Katipo spiders

Photo of a katipo spider, which is dark brown with a round abdomen. It has an orange stripe on its back, which is wavy with a white outline.
Female katipo spider, photo by Jess Costall / CC BY 2.0.

Bites

Because of the katipo’s increasing rarity and non-aggressive nature bites are rare.

Typical symptoms of katipo bites include pain at the bite site, which may spread to other areas, becoming more intense over the next few hours. People may also experience sweating, difficulty in breathing and abdominal cramps.

Redback spiders

Photo of a redback spider, which is a dark brown, with long legs and a thin red stripe on its round abdomen.
Redback spider, photo by Repat / CC BY-SA 3.0.

Bites

Redbacks will only bite when disturbed or trapped in clothing, and bites are rare.

The bite feels like a sharp pain similar to a pinprick. The bite may lead to localised redness, pain and sweating. Occasionally the pain and sweating may spread and stomach pain may occur. Aches in muscles and joints, nausea and vomiting, and increased heart rate and blood pressure can result.

White-tailed spider

Photo of a white-tailed spider, which is brown, with reddish legs and a long body. It has a white spot at its 'tail'.
White-tailed spider, photo by Phil Bendle / CC BY-NC-ND 3.0.

The usual white-tailed spider bite can be painful but the initial burning feeling, swelling, redness and itchiness at the bite site usually goes and there are no long-lasting effects.

White-tailed spider bites are not considered poisonous to humans. A recent Australian study has shown no evidence linking necrotic ulcers (destroyed skin) to white-tailed spider bites.

Catch the culprit

With all suspected spider bites it is important to know which spider may have been responsible. Try to capture the spider without endangering anybody and take it to the doctor or hospital with you, or describe it carefully for identification.

With suspect spiders:

  • approach with caution – do not handle
  • you may wish to use a fly spray that claims to be effective on spiders to stun the spider before killing it and/or placing it in a sealed jar.

What to do if you think you have been bitten by a katipo or redback spider

If you suspect you have been bitten by a katipo or redback spider you need to seek urgent medical attention at your nearest hospital, medical centre or doctor. Even if you do not immediately experience symptoms beyond the ‘pin prick’ of the bite you still need medical advice.

DO

  • clean the wound with antiseptic or warm soapy water
  • place ice on the bite (not directly onto the skin) prior to travelling.

DO NOT

  • apply pressure to the wound
  • consume alcohol after being bitten.

Do not panic as serious reactions are uncommon and unlikely to develop in less than three hours. Hospitals can provide safe and effective treatment. Venom is not always introduced with the bite. If it is, most reactions to the venom are moderate.

What to do if you think you have been bitten by a white-tailed spider

If you suspect you have been bitten by a white-tailed spider only simple first aid is necessary, as with any puncturing of the skin, as these spiders do not cause skin damage or ulcers:

  • clean the bite area with antiseptic or warm soapy water
  • place ice on the bite (not directly onto the skin) to reduce any pain or swelling.

For any suspected spider bite, see a doctor if the bite area becomes very red or painful, blisters, appears infected, or forms an ulcer.

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