Jellyfish stings

Some kinds of jellyfish deliver a painful sting. Find out what to do if you or a family member gets stung.

On this page:

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

Identify the jellyfish

It’s helpful to know the type of jellyfish causing the sting as treatments options can vary.

Bluebottles

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.

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 when you treat the sting. Read how to treat the sting. This is the jellyfish most found in New Zealand waters.

Lion’s-mane jellyfish

The lion’s-mane jellyfish, which is a 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

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.

Mauve stinger

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

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.

Self care for jellyfish stings

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

Treatment for a bluebottle sting

Follow these steps to treat the sting area:

  1. Splash on lots of sea water straight from the sea immediately.
  2. Pull the tentacles off with a dry towel. Wear gloves if you have some.
  3. If you can, pour over warmed up sea water. You can put hot water into the sea water to add warmth.
  4. Immerse the stung area in heated tap water for 20 minutes. Have it as hot as the person can bear. Or use a wet, hot towel.
  5. Elevate the area, apply ice packs and take pain relief.

Note: Vinegar does not help with blue bottle stings.

Treatment for other jellyfish sting

Follow these steps to treat the sting area:

  1. Apply sea water to the area. If you are able to warm up some sea water, pour this over the area (even urine is better than nothing!).
  2. Do not apply fresh water as this will activate the stingers.
  3. Pull the tentacles off with a dry towel. Wear gloves if you have some, but you can use your fingers – although wash them immediately afterwards.
  4. Immerse the stung area in heated tap water for 20 minutes. Have it as hot as the person can bear. Or use a wet, hot towel.
  5. Elevate the affected area for 24 hours, and apply ice to decrease the pain.ollow these steps to treat the sting area:

Pain medications and precautions

  • If necessary, take pain relief such as paracetamol.
  • 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

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.

Take non-steroidal anti-inflammatory drugs (NSAIDs) with food or milk to prevent stomach irritatio

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.

 Serious allergic reaction or anaphylaxis

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
  • hoarse voice
  • difficulty swallowing or throat tightness
  • signs of shock (pale skin, rapid pulse and fainting).

However, it is rare for a patient to have an anaphylaxis to jellyfish, even if they are stung on the face or neck.

This topic sheet was provided in association with  Healthline.

Back to top