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Jellyfish Stings

Key Points

  • Check the Safeswim website for those beaches affected by  stinging and biting marine life 
  • Take precautions to reduce the risk of stings, rashes and bites
  • Learn how to treat stings and rashes
  • Notify Auckland council on (09) 301-0101 if you become aware of stings and rashes from marine-life at Auckland beaches.
  • Ask a pharmacist for advice on topical creams to treat stings and rashes
  • If you are concerned or symptoms are severe visit a doctor or call the nurses at Healthline for advice on 0800 611 116. Healthline operates 24 hours a day,

Rashes, stings and bites from swimming at the beach

Rashes, itches, stings and bites from swimming or paddling in the sea can occur around the Auckland coast at some times of year.  These can be caused by several types of sea life, including: 
  • tiny transparent jelly fish and anemone larvae which get into your swimming costume and cause “seabathers’ eruption”
  • larger jelly fish and other organisms which float in the water that sting exposed skin 
  • animals such as crabs which nibble and bite your feet
  • some types of seaweed which can cause a rash 

Seabathers’ Eruption

People who get itchy, sore rashes under their swimming costume after swimming at a beach are likely to have been stung by tiny, transparent jellyfish or anemone larvae. The rash is called “seabather’s eruption” and it is the skin’s reaction to the toxin injected by jellyfish or anemone larvae.  

This rash is often called “sea lice bites”, but sea lice are actually a parasite of fish and they can produce a rash on uncovered skin.  

What does  seabather’s eruption look and feel like?

Figure 1: Seabathers' Eruption rash.  Source: DermNet NZ

Symptoms of seabather’s eruption include pain, burning and itching. The rash appears as red swollen marks on areas of skin that were covered by swimwear.   People can get skin tingling before leaving the sea, and the rash tends to occur after getting out of the water.  The rash may not appear until several hours after being in the sea. The rash and itchy can vary from mild to severe lasting up to a week or more. Children and those with a severe reaction can become unwell with headaches, nausea and lethargy for several days. 

How does seabather’s eruption occur?

Warm weather and onshore winds bring tiny jellyfish and anemone larvae close to the shoreline and being so small, they can get trapped unnoticed in swimwear, or in peoples’ hair while swimming. As a swimmer gets out of the sea, water drains from the swimwear and traps the jellyfish between the fabric and the skin, causing the stinging cells to release their toxin.  The toxin can also be released by washing in fresh water and rubbing affected skin with a towel.  

What to do

  • Remove the swimming costume, and wash the affected area.  Salt water (without jellyfish) is best.  Fresh water can be used, but sometimes can make the rash worse.Hydrocortisone cream (1%) applied 2-3 times a day over 1-2 weeks is the most useful treatment.  Calamine lotion, antihistamines, and anti-inflammatory medicines such as ibuprofen can also help reduce symptoms.  Ask your pharmacist for advice.
  • If you are concerned or if symptoms are severe see a doctor or call Healthline for advice on 0800 611 116. Healthline operates 24 hours a day, seven days a week.  
  • Treatment from the doctor will vary according to the severity of symptoms and could include pain medication, antihistamine, steroids or antibiotics.
  • Let Safeswim at Auckland Council know which beach you got the rash by phoning (09) 301-0101. 

Taking precautions 

  • Check the Auckland Council’s Safeswim website for beaches affected by jellyfish. Avoid swimming in baggy clothes, instead wear fitted swimwear as this traps less tiny jellyfish.
  • Do not dry yourself with a towel after swimming as this activates the stings.
  • Do not sit in the swimwear for long periods , instead remove your swimwear and if possible shower immediately. A saltwater shower is best although a freshwater shower is almost as good. 
  • When you get home thoroughly launder your swimwear as stinging can happen even when the jellyfish is dead. 
  • Wearing a mask or goggles underwater enables you to see and avoid larger jellyfish. A wetsuit will provide protection with areas of skin that are covered.

What about larger jellyfish?

The bluebottle jellyfish (Physalia utriculus) is the species that most commonly cause stings in New Zealand. The lion’s mane jellyfish (Cyanea capillata) can also wash up on beaches in large numbers, these stings are generally mild. Other jellyfish may also sting but are unlikely to cause major health effects.


Figure 2: Jellyfish sting. Source:DermNet NZ

What to do if you are stung?

  • Remove any visible tentacles or stings attached to the skin - but do not touch the tentacles or stings with your bare hands. Tweezers can be helpful. 
  • Place the affected area in warm water.
  • If someone stung by a jellyfish has difficulty breathing or loses consciousness call 111 and ask for an ambulance.
ARPHS is a partner with the Auckland Council in the Safeswim programme that publishes information about the health risks from popular beaches in the region. The information on the Safeswim website is updated regularly and covers water quality, tides, sea conditions, advice about sun protection and beach hazards.

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