Stings, marine creatures

Page last reviewed: 13/07/2011

There are a number of sea creatures that can cause injury by biting or stinging. These include:

  • sea anemones
  • sea urchins
  • hydroids
  • cone snails
  • stone fish
  • fireworms
  • stingrays
  • jellyfish

Hydroids are plant-like animals that are closely related to jellyfish.

Marine creatures usually sting as a defence mechanism against predators. Fortunately, in the seas around Ireland, there are only a few types of marine creatures that sting. These include:

  • weever fish
  • stingrays
  • sea urchins
  • jellyfish

This information focuses on marine creatures found in Irish waters. If you are travelling abroad, it is a good idea to familiarise yourself with animals and plants that can cause injury in the countries you are visiting. See Useful links.

Weever fish

The weever fish is a small, sandy coloured fish that usually lies buried in the sand on the seabed waiting for prey to swim past.

Weever fish have poisonous spines on their back and gills. Most people are stung on their feet by weever fish after accidentally stepping on them.

Stingrays

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

Most species of stingray live in the sea, although some are found in fresh water. They often swim in shallow water and spend most of the time near the seabed buried in the sand.

As with weever fish, most stingray stings occur to the lower legs, ankles and feet when a person accidentally steps on one in shallow water.

Sea urchins

Sea urchins are small, circular creatures with a bony shell covered in spines. They live in seas throughout the world and are commonly found in the shallows, on rocks and in seaweed.

The spines of sea urchins are sharp and hard and can cause puncture wounds. Between the spines, small organs, called pedicellariae, contain poison that is released as a defence mechanism.

Jellyfish

Jellyfish are mushroom-shaped creatures that have many 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.

Jellyfish live in seas throughout the world and are found at a wide range of depths, although they often float near the surface. In recent years, during the warmer months, large swarms of jellyfish have become increasingly common in the seas around Europe, such as the Mediterranean.

Experts believe the increase in jellyfish numbers may be the result of increasingly warmer weather conditions combined with overfishing of their natural predators.

Portuguese man-of-war

The Portuguese man-of-war is a large, poisonous, jellyfish-like creature but it is not actually a jellyfish. As the treatments for the two species are different, it is important not to confuse them. 

The Portuguese man-of-war is sometimes found in Irish waters and has a large, gas-filled bladder that is a purple-blue colour. It floats on the surface of the water and, like a jellyfish, has long, thin tentacles that hang below the water.

The sting of a Portuguese man-of-war can be painful but rarely causes death. If you come across one that has been washed up on the beach, do not touch it as its tentacles remain venomous and can still sting you.

 

Page last reviewed: 13/07/2011

If someone has been stung by a marine creature, such as a stingray or jellyfish, seek the assistance of someone who has been trained in first aid, such as a lifeguard.

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

After being stung, some people may experience an allergic reaction known as anaphylaxis, or anaphylactic shock, which can sometimes be fatal. Any adverse allergic reaction should be treated as a medical emergency by ringing 999 to request an ambulance.

Weever fish

A sting from a weever fish can cause the following symptoms:

  • severe pain
  • itching
  • swelling (inflammation)
  • redness
  • numbness
  • tingling
  • nausea
  • vomiting
  • headache
  • joint ache
  • abdominal cramps
  • lightheadedness
  • temors (shaking)

If a person has a more serious reaction to a weever fish sting, they may experience:

  • an abnormal heart rhythm (arrhythmia)
  • shortness of breath
  • weakness
  • paralysis
  • seizures (fits)
  • a drop in blood pressure
  • episodes of unconsciousness

Death may occur in very severe cases.

When to seek medical advice

If someone has been stung by a weever fish, seek medical assistance immediately. Any spines left in the foot will need to be carefully removed.

Sea urchins

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

If you have been stung by a sea urchin, and you have received puncture wounds in several places, you may experience more severe symptoms including:

  • tiredness
  • weakness
  • aching muscles
  • shock
  • respiratory failure
  • paralysis (an inability to move the affected area)

In rare cases, severe injuries from sea urchins have been known to cause death.

When to seek medical advice

Following a sea urchin sting or puncture wound, seek immediate medical attention if the person has:

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

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

Stingrays

The hard, sharp barb of a stingray can cause a jagged cut or puncture wound in a person's flesh. The venom produced by a stingray's sting can also result in the breakdown of tissue, and severe pain that can last for up to 48 hours.

Other symptoms following a stingray sting include:

  • inflammation (swelling) of the affected area
  • bleeding from the wound
  • sweating
  • low blood pressure (hypotension)
  • feeling faint, weak, and dizzy
  • nausea
  • vomiting
  • diarrhoea
  • headache
  • shortness of breath
  • seizures (fits)
  • muscle cramps
  • irregular heart beat (arrythmia)

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

When to seek medical advice

Always seek immediate medical assistance if you or someone you know has been stung by a stingray. Alert a lifeguard if there is one nearby, before dialling 999 to request an ambulance.

A stingray sting should be dealt with by healthcare professionals at the emergency and accident (A&E) department of a hospital. If the sting is still in the site of the injury, it will need to be carefully removed. The puncture wound will need to be cleaned and dressed.

Following a sting, it is likely that you will have symptoms such as faintness, dizziness, and sweating as a result of the venom being absorbed into your blood stream. You may need to be treated with antibiotics and a tetanus booster injection.

Seek immediate medical attention if there is inflammation (swelling) around the site of the injury, or if there are signs of an infection, intense skin irritation and redness, and/or a high temperature (fever) of 38C (100.4F) or above.

Jellyfish

If you are stung by a jellyfish, you will experience some immediate symptoms such as:

  • severe pain
  • itching
  • a rash
  • raised welts (raised, circular areas on the skin)

Other symptoms that you may have include:

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

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

When to seek medical advice

If someone has been stung by a jellyfish, seek immediate medical assistance by dialling 999 if 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 been stung on a large area of the body or the face or the genitals
  • there is severe pain, itchiness or inflammation (swelling) around the sting

Portuguese man-of-war

If someone has been stung by a Portuguese man-of-war, they may have the following symptoms:

  • a red line with small, white lesions
  • and, in severe cases, blisters and welts (raised areas of skin) may develop

If you are stung in the eye, it is likely that you will have:

  • pain and inflammation (swelling)
  • watering eye
  • blurred vision
  • increased sensitivity to light

Following a sting by a Portuguese man-of-war, severe allergic reactions can sometimes occur. However, deaths as a result of a sting are rare.

When to seek medical advice

If someone is stung by a Portuguese man-of-war, seek medical attention if:

  • the pain is severe and lasts for 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 38C (100.4F) or more

Seek immediate medical attention if the person has a severe allergic reaction after being stung.

Glossary

Nausea
Nausea is when you feel like you are going to be sick.
Pain
Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.
Wheezing
Wheezing is the whistling sound made during breathing when the airways are blocked or compressed.
Blood
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Anaphylactic shock
Anaphylactic shock is a severe and sometimes life-threatening allergic reaction, causing swelling of body tissues and a drop in blood pressure.
Stomach
The sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.
Swelling
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
Heart
The heart is a muscular organ that pumps blood around the body.
Allergic
An allergen is a substance that reacts with the body's immune system and causes an allergic reaction.

Page last reviewed: 13/07/2011

Weever fish

Weever fish stings should be treated as outlined below.

  • Any large spines should be carefully removed from the wound using tweezers. 
  • To control the pain, the affected area should be immersed in hot water (as hot as can be tolerated) for between 30-90 minutes. This can be repeated if necessary. When the area has been numbed, be careful not to burn it with the hot water.
  • Thoroughly clean the wound using soap and water, before rinsing with fresh water. Do not cover the wound.
  • If there is itching, hydrocortisone cream can be applied two to three times a day. However, this should be stopped immediately if any signs of infection develop.
  • If the skin is red and badly inflamed, a topical antibiotic cream or ointment should be applied three times a day.
  • Pain and inflammation (swelling) can be treated with painkillers, such as paracetamol and ibuprofen. Children who are under 16 years of age should not take aspirin.  
  • If infection occurs, oral antibiotics may be prescribed. You should continue to take them for a minimum of five days after the signs of infection have disappeared. Before starting treatment, inform the healthcare professional who is treating you if you are allergic to any form of medication. Some antibiotics can cause sensitivity to the sun, so if you are exposed to sunlight, use a sun cream with a sun protection factor (SPF) of at least 15.
  • Cardiopulmonary resuscitation (CPR) may be required if the patient stops breathing and does not have a pulse.

Sea urchins

Sea urchin puncture wounds and stings should be treated as outlined below.

  • Any large spines should be carefully removed from the wound using tweezers.
  • The pedicellariae (small venomous organs) can be removed by putting shaving cream on the affected area and using a razor blade to gently scrape them out.
  • To control the pain, the affected area should be immersed in hot water (as hot as can be tolerated) for between 30-90 minutes. This can be repeated if necessary. When the area has been numbed, be careful not to burn it with the hot water.
  • Pain and inflammation (swelling) can be treated with painkillers, such as paracetamol and ibuprofen. Children who are under 16 years of age should not take aspirin.
  • Scrub the wound thoroughly using soap and water, then rinse it with fresh water. Do not close the wound with tape.
  • If the skin is red and badly inflamed, topical antibiotic cream or ointment should be applied three times a day.
  • If infection occurs, oral antibiotics may be prescribed (tell the healthcare professional treating you if you are allergic to any medication). If you are prescribed antibiotics, make sure that you finish the complete course. Some antibiotics can cause sensitivity to the sun, so if you are exposed to sunlight, use a sun cream with a sun protection factor (SPF) of at least 15.

Stingrays

Stingray stings can be treated in three main ways:

  • monitoring the person's condition
  • providing pain relief
  • treating the wound

Monitoring

If someone has been stung by a stingray and has low blood pressure (hypotension), they may be given medication and intravenous fluids (fluids directly into a vein). In severe cases, hospital admission may be required in order to closely monitor your condition.

Treating pain

There is no antidote to stingray venom. However, the pain from a sting can be relieved by:

  • placing the affected area in hot water (as hot as can be tolerated) for between 30-90 minutes being careful not to burn it with the hot water; this can be repeated if necessary
  • using pain relieving medication (may need to be given given intravenously -direct through a vein)
  • using pain numbing medication

Wound care

Once the wound has been cleaned and the sting has been removed (if necessary), the doctor can look for any further damage. A tetanus booster may be needed if it is more than five years since your last tetanus injection.

Following a stingray sting, you will usually be given antibiotics because there is a high risk that the wound will have been contaminated by bacteria in the sting and the seawater.

Initially, the wound will be left open before being closed with stitches after about 48 hours if it has not become infected. Surgery may be required if there is damage to vital structures, such as nerves, tendons, or arteries (blood vessels).

Jellyfish

If someone have been stung by a jellyfish, the following treatment is recommended.

  • The affected area should be soaked in vinegar for between 15-30 minutes to prevent further toxin from being released. If vinegar is not available, rinse the area with alcohol or seawater (not fresh cold or hot water).
  • Do not rub the area, or apply ice.
  • Remove any tentacles with tweezers or a clean stick (wear gloves if they are available).
  • Apply shaving cream to the affected area and use a razor blade, or a credit card, to remove any nematocysts (small poisonous sacs) that are stuck to the skin.
  • If the eyes are affected, they should be rinsed with a saline (salt) solution, such as artificial tears, and dabbed with a towel that has been soaked in vinegar. Do not apply vinegar directly to the eyes.
  • Stings to the mouth should be treated with a watery vinegar solution. Mix a quarter of a cup of vinegar with three-quarters of a cup of water, and gargle with the solution before spitting it out. Do not swallow the solution.
  • Pain and inflammation (swelling) can be treated with painkillers, such as paracetamol and ibuprofen. Children under 16 years of age should not take aspirin.
  • Cardiopulmonary resuscitation (CPR) may be required if the patient stops breathing and does not have a pulse.

Portuguese man-of-war

If someone has been stung by a Portuguese man-of-war, the following treatment is recommended.

  • remove any tentacles from the skin but be careful not to touch them with your fingers to avoid being stung (use tweezers, or gloves)
  • use salt water to wash the affected area (avoid using fresh water)
  • do not use vinegar to wash the affected area because it can make the symptoms worse
  • rinse the affected area with hot water to help ease the pain of the sting

If the sting is to the eyes, rinse them using a saline (salt) solution, such as artificial tears. Seek immediate medical assistance if, after washing your eyes, they continue to water, still remain painful and swollen, or if your vision is blurred.

Box jellyfish

Box jellyfish are native to Australia and are very dangerous. Medical assistance should be sought immediately following a box jellyfish sting. While waiting for help to arrive, keep the affected area as still as possible and soak it with vinegar.

If you are in a remote location where medical help is unavailable, the affected area (and tentacles) should be soaked for 10 minutes or more before trying to remove the tentacles.

Glossary

Antibiotics
Antibiotics are medicines that can be used to treat infections caused by micro-organisms, usually bacteria or fungi. For example amoxicillin, streptomycin and erythromycin.

Page last reviewed: 13/07/2011

Many marine creatures, such as sea urchins and sea anemones, have a protective coating on them which, if rubbed off, makes them vulnerable to bacteria and parasites. Touching marine animals, such as coral, can also damage it.

If you touch or handle marine creatures they may become stressed and sting you. Therefore, it is best to avoid touching or handling them.

First aid training and kit

If you spend a lot of time in the sea for work or leisure, it is a good idea to get some basic first aid training and to carry a basic first aid kit with you. The kit should contain useful items, such as tweezers, gloves, a saline (salt) solution, painkillers and vinegar.

If you have a known allergy to insect stings, you should carry appropriate medication with you, such as an adrenaline injection kit. Make sure the people you are with are aware that you have an allergy, and know how to administer the medication in case you are unable to do so yourself.

Weever fish

As weever fish are commonly found on the seabed, buried underneath the sand, it is a good idea to wear footwear, such as waterproof sandals, when walking in the shallows.

Scuffing your feet along the seabed when you walk will also scare away any weever fish buried in the sand ahead of you.

Sea urchins

To avoid being stung by a sea urchin, be careful when walking in rocky areas, such as those around the shoreline. Take particular care when you are entering or exiting the sea on beaches where there are rocks and seaweed.

Avoid handling sea urchins. Like many marine creatures, sea urchins are highly sensitive, and may become stressed if touched.

Stingrays

As with weever fish, to avoid being stung by a stingray, you should wear appropriate footwear in the shallows, and scuff your feet through the sand to disturb any stingrays that are lying in your path. You should also avoid intentionally touching, or handling, a stingray.

Jellyfish

To avoid being stung by a jellyfish, try to avoid swimming in areas where they are known to be.

If you are swimming in areas where there are jellyfish, familiarise yourself with the types of jellyfish that are found in the area, and look out for them floating near the surface of the water.

Wearing protective clothing, such as a wet suit, will help prevent being stung by a jellyfish should you come into contact with one.

Do not touch jellyfish (or Portuguese men-of-war) that have been washed up on the beach because they can continue to release toxin for a long time and still sting you.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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