Jellyfish stings and other sea creature stings

Fortunately, there are only a few types of sea creatures that sting in the seas around the UK.

Information written and reviewed by Certified Doctors.

Contents

Introduction

Fortunately, there are only a few types of sea creatures that sting in the seas around the UK.

The five main types of stinging sea creatures found in UK, and other, waters are:

  • weever fish
  • stingrays
  • sea urchins
  • jellyfish
  • Portuguese man-of-war

These are described below.

Weever fish

Weever fish are small, sandy coloured fish that usually lie buried in the sand on the seabed.

They have poisonous spines on their back and gills that can sting people, usually on the feet or hands.

Stingrays

Stingrays are flat, circular or diamond-shaped fish that have a sharp, serrated barb underneath their tail.

As with weever fish, most people stung by a stingray are stung on their lower legs, ankles and feet after accidentally stepping on one in shallow water.

Sea urchins

Sea urchins are small, round sea creatures with a bony shell covered in spines. They're usually found in the shallows, on rocks and in seaweed.

Sea urchin spines are hard, sharp and can cause puncture wounds. Between the spines are small organs that contain poison which is released as a defence mechanism.

Jellyfish

Jellyfish are mushroom-shaped creatures that often float near the surface and have long, thin tentacles on the underside of their bodies.

The tentacles are covered with small poisonous sacs called nematocysts which, if touched, produce a nasty sting.

In recent years, during the warmer months, large groups of jellyfish have become increasingly common in the seas around Europe.

Portuguese man-of-war

A Portuguese man-of-war is a large, poisonous jellyfish-like creature (although it's not a jellyfish) with a large purple-blue, gas-filled bladder and tentacles that hang below the water.

They're usually found in tropical waters but some have been spotted in UK waters or found washed up on beaches. The sting can be painful but rarely causes death.

Signs and symptoms

The visual signs and symptoms of a sting will vary depending on what has stung you. Weever fish and sea urchins usually sting your foot and often leave spines in the wound.

Stingrays can leave a large, jagged cut or puncture wound on your skin, and jellyfish and Portuguese men-of-war will often leave raised blisters on the skin in the shape of their own tentacles.

All stings are painful and cause swelling, inflammation or raised areas of skin (welts) and nausea. You may also have other symptoms, depending on what has stung you.

Read more about the symptoms of sea creature stings.

When to seek medical help

Seek medical assistance if you’ve been stung while in the sea and your symptoms are severe, such as severe, prolonged pain that lasts for more than an hour, or if you have other severe effects such as:

  • chest pain or breathing problems
  • severe redness and swelling around the affected area
  • fits or seizures

You should also seek medical help if you know that you’ve been stung by a stingray, or if you’ve been stung on a particularly sensitive part of your body, such as your face or genitals.

Less severe marine creature stings can be treated yourself using first aid techniques.

Read more about how marine creature stings are treated, both at home and in hospital.

Avoiding stings in the sea

It's rare to be stung in the seas around the UK, but there are precautions you can take to avoid being stung, including:

  • observing beach warning signs
  • not touching or handling sea creatures that sting
  • wearing protective clothing, such as a wetsuit or waterproof footwear
  • scuffing your feet as you walk in shallow water to warn any sea creatures that you're approaching

Read more about how to prevent being stung in the sea.

Symptoms

If you or someone else has been stung in the sea, get help from someone with first aid training, such as a lifeguard.

Further medical assistance may be needed if the symptoms of a sting are severe and very painful.

After being stung, some people may have a severe allergic reaction, known as anaphylaxis or anaphylactic shock, which can sometimes be fatal.

Any adverse allergic reaction should be treated as a medical emergency. Call for an ambulance.

Weever fish

A sting from a weever fish can cause:

  • severe pain for the first two hours
  • itching
  • swelling (inflammation)
  • numbness
  • nausea or vomiting
  • headache
  • abdominal cramps
  • tremors (shaking)

Someone who has a more serious reaction to a weever fish sting may also experience:

  • an abnormal heart rhythm (arrhythmia)
  • shortness of breath
  • weakness
  • paralysis (an inability to move the affected area)
  • seizures (fits)
  • a drop in blood pressure
  • episodes of unconsciousness

Although weever fish stings are usually very painful, serious reactions are uncommon and deaths are extremely rare.

Seek immediate medical assistance if you or someone else has been stung by a weever fish. Any spines left in the foot will need to be carefully removed.

Stingrays

A stingray's sharp barb can leave a jagged cut or puncture wound in the flesh, and the venom from the sting can cause pain and swelling.

Other symptoms may include:

  • skin irritation
  • sweating
  • low blood pressure (hypotension)
  • feeling faint, weak and dizzy
  • nausea and vomiting
  • diarrhoea
  • headache
  • shortness of breath
  • seizures (fits)
  • muscle cramps

Deaths from stingray injuries are rare, but there have been cases where people have died following a puncture wound to the heart or abdomen.

Always seek immediate medical assistance if you or someone else has been stung by a stingray. Alert a lifeguard if there is one nearby before dialling to request an ambulance.

A stingray sting should be dealt with at the accident and emergency department of the nearest hospital.

Sea urchins

A puncture wound from a sea urchin can be painful and cause inflammation and redness around the affected area.

If you have puncture wounds in several places, you may experience more severe symptoms including:

  • tiredness
  • weakness
  • aching muscles
  • shock
  • respiratory failure
  • paralysis

In rare cases, people have died from severe sea urchin injuries.

Get immediate medical attention if your symptoms include:

  • breathing problems
  • chest pain
  • signs of infection, such as increased redness and swelling in the affected area and a high temperature (fever) of 38°C (100.4°F) or above

Medical assistance is also required if there are spines in or near a joint because they may need to be surgically removed.

Jellyfish

If you're stung by a jellyfish, you'll feel severe pain immediately and develop an itchy rash and welts (raised, circular areas on the skin) where the tentacles have touched you.

Other symptoms may include:

  • nausea or vomiting
  • diarrhoea
  • abdominal pain
  • muscle spasms
  • numbness or tingling
  • swollen lymph nodes (the small nodules found in several places around the body, including the groin and armpit)

In rare cases, a serious reaction to a jellyfish sting can result in breathing difficulties, coma or even death.

If you or someone else has been stung by a jellyfish, seek immediate medical assistance if you or they:

  • are having problems breathing or swallowing
  • have chest pain
  • have severe pain at the site of the sting
  • are very young or elderly
  • have a sting that affects a large area of the body
  • have been stung on the face or genitals
  • have severe pain, itchiness or swelling around the sting

Portuguese man-of-war

A Portuguese man-of-war sting may cause a red line with small, white lesions. In severe cases, blisters and welts (raised, circular areas of skin) may also appear.

A sting from a Portuguese man-of-war can sometimes cause a severe allergic reaction, although deaths as a result of a sting are rare.

Following a sting, seek medical attention if:

  • the pain is severe and lasts more than an hour
  • the rash gets worse
  • there are signs of infection, such as increased redness and swelling in the affected area and a high temperature (fever) of 38°C (100.4°F) or above

Read more about how sea creature stings are treated.

Treatment

Treatment for stings in the sea will vary depending on what has stung you and, in some cases, how severe your reaction is.

You can treat some stings yourself using first aid. However, if the symptoms are more serious, such as severe pain, swelling or difficulty breathing, call for an ambulance immediately.

Read more about symptoms of marine creature stings, including advice about when to seek hospital treatment.

Weever fish

If you're stung by a weever fish, it's important to get first aid and medical attention immediately.

To control the pain, the affected area should be immersed in hot water (as hot as can be tolerated) for 30-90 minutes. However, be careful not to burn your skin. This can be repeated if necessary.

You can use simple painkillers, such as paracetamol, to relieve remaining pain.

Any large spines should be carefully removed from the wound using tweezers (avoid touching the spines with your bare hands). Clean the wound using soap and water and then rinse it with fresh water. Do not cover the wound.

Spines embedded in or near joints or tendons should be assessed in A&E. X-rays may be required and the spines may need to be surgically removed.

A severe allergic reaction (anaphylaxis) will need to be treated in hospital immediately.

Anti-tetanus prophylaxis (an injection) may be needed if you or the affected person is not fully vaccinated.

Aftercare

If there is itching, hydrocortisone cream can be applied 2-3 times a day. However, this should be stopped immediately if there are any signs of infection (severe inflammation and redness).

Pain and inflammation can also be treated with painkillers, such as paracetamol and ibuprofen.

If an infection develops, a course of antibiotics may be prescribed. They should be taken for a minimum of five days after the signs of infection have disappeared.

Sea urchins

Sea urchin puncture wounds and stings are treated in a similar way to weever fish stings. If there are signs that you or someone you're with has had a severe allergic reaction (anaphylaxis), call for an ambulance.

Immerse the affected area in hot water (as hot as can be tolerated) for 30-90 minutes. Again, be careful not to burn your skin.

Any large spines should be carefully removed from the wound using tweezers. The small, venomous organs (pedicellariae) can be removed by applying a small amount of shaving cream to the affected area and using a razor blade to gently scrape them out.

Scrub the wound using soap and water and then rinse it with fresh water. Do not close the wound with tape.

Aftercare

Pain and swelling can be treated with painkillers, such as paracetamol and ibuprofen.

If the skin is red and badly inflamed, a topical antibiotic cream or ointment should be applied three times a day.

Stingrays

Alert a lifeguard and call to request an ambulance if you're stung by a stingray.

There's no antidote to stingray venom but pain from a sting can be relieved by:

  • immersing the affected area in hot water (as hot as can be tolerated) for 30-90 minutes
  • using pain-relieving medication given directly through a vein (intravenously)
  • using pain-numbing medication (local anaesthetic)

Once the wound has been cleaned and the sting removed (if necessary), the doctor will be able to look for further damage. You may need a tetanus booster if it's more than five years since your last tetanus injection.

After being stung by a stingray, you'll usually be given antibiotics because there's a high risk of the wound being contaminated by bacteria in the sting and the seawater, which could lead to an infection.

The wound will initially be left open before being closed with stitches after about 48 hours if it hasn't become infected. In rare cases, surgery may be needed if the sting affects the tendons or blood vessels.

Jellyfish

Most jellyfish stings are mild and don’t require treatment or can be treated yourself.

However, seek medical assistance, call for an ambulance, if there are severe symptoms, such as difficulty breathing, chest pain, or if a large or sensitive area of the body, such as the face or genitals, has been stung.

Someone stung by a jellyfish should be treated out of the water. They should stay as still as possible while being treated because movement increases the risk of toxins being released into the body.

Any remaining tentacles should be removed using tweezers or a clean stick (wear gloves if they're available). Applying an ice pack to the affected area will help reduce pain and inflammation.

Vinegar is no longer recommended for treating jellyfish stings because it may make things worse by activating unfired stinging cells. The use of other substances, such as alcohol and baking soda, should also be avoided.

Ignore any advice you may have heard about urinating on the sting. It's unlikely to help and may make the situation worse.

Applying shaving cream to the affected area will help prevent the spread of toxins. Use a razor blade, credit card or shell to remove any nematocysts (small poisonous sacs) that are stuck to the skin.

Aftercare

After a jellyfish sting, any pain and swelling can be treated with painkillers, such as paracetamol and ibuprofen.

Portuguese man-of-war

Portuguese man-of-war stings can be treated in a similar way to jellyfish stings (see above).

As with jellyfish stings, don't use vinegar or alcohol to wash the affected area because it can make the pain worse

Instead, after carefully removing any remaining tentacles from the skin (see above), thoroughly wash the affected area with seawater (not fresh water). Afterwards, soak the area in hot water to help ease the pain.

Pain from a Portuguese man-of-war sting will usually last about 15-20 minutes. Seek immediate medical assistance if the pain lasts more than an hour, or if the affected area becomes infected.

Prevention

If you're going to swim in the sea, there are things you can do to avoid being stung and to ensure that you have easy access to medical care.

For example, you can:

  • Observe warning signs on the beach - warning signs will often be put up after sightings of groups of jellyfish or Portuguese men-of-war.
  • Swim near a lifeguard - if you're stung by a sea creature, you will usually need immediate first aid or, in severe cases, a means of contacting an ambulance.
  • Do not touch or handle stinging sea creatures - avoid touching jellyfish or Portuguese men-of-war washed up on the beach because even when they're dead, their tentacles can sting.
  • Wear protective clothing such as a wetsuit or waterproof footwear - as weever fish, stingrays and sea urchins are often found in shallow water, wearing rubber-soled shoes or sandals will help protect your feet while in shallow water or rocky areas; wearing a wetsuit will help protect against jellyfish stings if you're swimming for prolonged periods of time in deeper water.
  • Scuff your feet when walking in shallow water - this will help disturb and scare off any stinging sea creatures that may be in your path.
  • Take care when walking in rocky areas or near seaweed - sea urchins are often found in shallow, rocky areas such as rock pools.

First aid training and kit

If you spend a considerable amount of time in the sea, it's a good idea to get some basic first aid training and to carry a basic first aid kit with you.

The kit should contain items useful for treating sea creature stings, such as a pair of gloves, tweezers, a saline (salt) solution and painkillers.

If you're allergic to insect stings, you should carry appropriate medication with you, such as an adrenaline injection kit. Make sure that people you're with are aware of your allergy and know how to administer the medication in case you're unable to do it yourself.

Content supplied by NHS Choices