Jellyfish stings

There are several kinds of jellyfish found in New Zealand – and some can deliver a painful sting. Find out which jellyfish to watch out for, and what to do if you or a family member gets stung.

Photo of a lion’s-mane jellyfish, a large, pale blue jellyfish with many tentacles.
Lion’s-mane jellyfish, photo by Jérôme Mallefet / CC BY-NC-SA 3.0.

The lion’s-mane jellyfish is a common stinging jellyfish. It can be found in colours from white to deep blue. It grows to almost 2 m across. Its tentacles can be up to 5 m long and are almost invisible.

The mauve stinger has only few stinging catch tentacles. It can grow to 40 cm across.

The Portuguese man-of-war (blue bottle) has a burning sting. It’s not a true jellyfish, which means there are some things you should do differently to treat the sting. These are described below.

Call 111 for an ambulance if you or someone else has been stung and has symptoms of a serious allergic reaction or anaphylaxis.

Photo of a mauve stinger, a purple jellyfish with several large tentacles hanging from the bell, and a few thinner catch tentacles.
Mauve stinger, photo by Hans Hillewaert / CC-BY-SA-3.0.

These symptoms include:

  • swelling around the lips and eyes
  • rapid development of a rash
  • shortness of breath or wheezing
  • chest tightness
  • severe dizziness or faints
  • persistent sneezing or coughing
  • hoarse voice
  • difficulty swallowing or throat tightness
  • signs of shock (pale skin, rapid pulse and fainting).

Self care for jellyfish stings

Photo of a washed up blue bottle, with a pale blue body which looks like you could pop it, and blue tentacles.
Washed-up blue bottle, photo by Pappito at en.wikipedia / CC-BY-SA-3.0.

If you or a family member has been stung by a jellyfish, get out of the water and follow these steps.

  • Apply wet sand or a towel soaked in sea water. If tentacles are still sticking to your skin, don’t try to pull them off.
  • If you are able to warm up some sea water, pour this over the area (even urine is better than nothing!). If you can get vinegar, pour this over the stung area (but do not use vinegar for blue bottle stings).
  • Do not apply fresh water as this will activate the stingers.
  • Wait five minutes and then wipe the tentacles off with a dry towel. Be careful not to get stingers on your hands – wear gloves if you have some.
  • For all stings except blue bottles, apply cool compresses to the affected skin.
  • For blue bottle stings, immerse the stung area in warm water (45°C) for 20 minutes.
  • Elevate the affected area for 24 hours.
  • If necessary, take pain relief such as Panadol.
  • Antihistamines such as Telfast, Claratyne and Phenergan may relieve itching and swelling. A cream with hydrocortisone will reduce inflammation. You can get these from your pharmacy.

Medicine precautions

  1. Do not give aspirin (acetylsalicylic acid) or aspirin-containing products to anyone 18 years or younger because of the risk of a serious illness called Reye's syndrome.
  2. Take non-steroidal anti-inflammatory drugs (NSAIDs) with food or milk to prevent stomach irritation. Do not give NSAIDs to anyone with:
    • NSAID-induced asthma
    • increased risk of bleeding, such as ulcer disease, a bleeding disorder, if taking blood thinners (anticoagulants), or following surgery, significant trauma or major dental work
    • an allergy to NSAIDs.

When to see your doctor

Call your doctor if you have been stung and have:

  • increasing numbness or difficulty breathing
  • signs of poisoning: abdominal pain, muscle cramps, nausea, vomiting
  • signs of infection later: increasing pain, redness, swelling, red streaks leading away from the sting, heat, discharge of pus, fever or chills
  • pain that is not controlled by following the self-care instructions
  • any new or worsening symptoms.
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