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Marine Envenomation (Main)

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Other Names

  • Jellyfish sting


  • This page refers to all marine envenomations
  • Venomous aquatic animals are hazardous to swimmers, surfers, divers, fishermen and any other marine water sport


  • United States exposures[1]
    • Jellyfish (31%),
    • Stingrays (16%)
    • Venomous fish venomous fish (including lionfish, catfish, and others) (28%)
    • Gastropods (6%)
  • 1,500 sting ray bites annually in United States[2]
  • World wide
    • Thousands of injuries but few fatalities[3]


  • Occurs primarily in tropical and equitorial bodies of water
    • Indopacific is most common for venomous species
  • Most envonmenations occur not as an attack but act of self defense when animal perceives danger
  • Over 100000, 100 of which are known to be poisonous (need citation)
  • Marine venoms are generally contain heat labile proteins which quickly denature with hot water
  • Always consider
    • Tetanus booster
    • Antibiotic prophylaxis (staph, strep, vibrio)
    • Always involve poison control if suspected toxicologic source (800-222-1222)
  • Think local and be familiar with what you can expect to see in your region
  • The vast majority of encounters are benign and just require reassurance
  • When in doubt, use warm water
  • No rule for micturition in any clinical setting
    • "The only time urinating on some one is indicated is between two consenting adults who are in to that sort of thing” - Dr Andrew Schmidt

Risk Factors

  • Swimmers
  • Surfers
  • Divers
  • Snorkling
  • Fishermen

Differential Diagnosis

Water Related Injuries

  • Hypothermia
  • Immersion Pulmonary Edema
  • Marine Envenomation
  • Diving Emergencies
  • Drowning
  • Near Drowning

Envenomations and Mimics

  • Marine Envenomations
    • Toxins (ciguatera, neurotoxic shellfish poisoning, paralytic shellfish poisoning, scombroid, tetrodotoxin
    • Stingers (stingray injury
    • Venomous fish (catfish, zebrafish, scorpion fish, stonefish, cone shells, lionfish, sea urchins)
    • Nematocysts (coral reef, fire coral, box jellyfish, sea wasp, portuguese man-of-war, sea anemones)
    • Phylum porifera (sponges)
    • Bites (alligator/crocodile, octopus, shark)
  • Other



  • Nematocysts are classified by the mechanism by which they inject their toxin
  • Cnidaria is the phylum under the animal kingdom
  • Generally, the treatment for these envenomations is inactivation of the toxin with 5% acetic acid (vinegar)

Seabather's Eruption

  • Not specific, due to exposure to nematocysts
  • Symptoms
    • Pruritic papules resembling insect bites in distribution of swim suit
    • Often occurs during a shower after swimming in ocean as fresh water ruptures larvae
  • Treatment
    • Treat skin with acetic acid 5%, or lidocaine-containing first aid remedy
    • Wash swim suit with hot water and detergent, then machine or sun dry

Sea Nettle

  • Taxonomy: Chrysaora specie
  • Location: West coast USA, SW Europe Atlantic Coast, Mediterranean


  • Taxonomy & Description
    • Physalia physalis, Physalia utriculus, AKA Blue Bottle
    • Location: found in Atlantic, Indian and Pacific oceans, including southern US
    • Not a true jellyfish
    • Formed by colonies of siphonophore with each unit a specialized animal of the same species
    • Underwater tentacles up to 30m (atlantic), 3m (pacific)
  • Symptoms
    • Local sharp pain immediately after the sting, followed by an erythematous maculopapular linear rash, local edema, and numbness
    • Rash improves at 24 hours, complete resolution by 72 hours
    • Complications: Skin necrosis, cardiorespiratory collapse, and rarely death
  • Treatment
    • Antivenom: None
    • Remove tentacles, preferably with forceps or gloved hand
    • Hot water (45°C) immersion for 10–20 min preferred over local application of ice-packs for pain control[4]
    • Avoid using vinegar or methylated spirits (can increase nematocyst firing)
    • Topical anesthetics can be considered after successful removal of all tentacle fragments.
    • Use oral or parenteral analgesics if pain persists

Fire Coral

  • Taxonomy & Description
    • Many species found worldwide on reef crests and in shallow waters (except Hawaii)
  • Symptoms
    • Symptoms: immediate pain and urticaria, sometimes progressing to hemorrhagic or ulcerating lesions
    • Pain resolves by 90 minutes, local symptoms by 72 hours
    • Less commonly: severe systemic symptoms include nausea, vomiting, muscle cramps, dyspnea, anxiety, abdominal pain, and headache.
  • Treatment
    • Apply acetic acid 5% (vinegar) to the skin.
    • Consider steroid cream or an oral antihistamine for symptomatic relief;
    • Consider oral corticosteroids if severe

Box Jellyfish

  • Taxonomy & Description
    • Chironex fleckeri AKA sea wasp, marine stinger
    • Location: tropical indo-pacific, has been seen in southeast United States
  • Sting
    • Timing: In Australia, 92% of the stings took place between October 1 and June 1
    • 83% were in shallow water (<1 m) between 3-6pm[5]
    • Sting is a medical emergency, potentially lethal
    • Responsible for at least 67 deaths in Australia[6]
    • Most people die 20 minutes after sting
  • Symptoms
    • Initial: Itchy red maculopapular rash, burning pain, edema, and the classical ladder-rung pattern lesion
    • Major: Patient is altered, somnolent, bradypneic, tachycardic, hypotensive
    • Cardiotoxic effect, nerve palsy, hemolysis, cardiopulmonary decompensation, shock, and death
    • Up to 25% of people die, more than sharks
  • Treatment
    • Antivenom: CSL Antivenom effective in first hour
    • Remove tentacles ASAP to reduce likelihood of lethal injury
    • Apply acetic acid 5% (vinegar) to the skin.
    • Hot water shower as tolerated for 10 - 20 minutes
    • Wound care: distal to proximal compression bandage shown to help in snake envenomations[7]
    • Analgesia: ice, topical, oral, parenteral
    • Medications: consider verapamil (some evidence, need citation), beta blockers, magnesium sulfate

Iurkandji Jellyfih

  • Taxonomy & Description
    • Carukia barnesi
    • Animal is small, 3 to 19 mm
    • Location: northern and western coasts of Australia
  • Symptoms
    • Initially: wheal, local erythema at the sting site
  • Irukandji Syndrome
    • Occurs 20m - 2hr after sting
    • Thought to be sympathetic nervous system stimulation.
    • Symptoms: severe abdominal, chest, limbs, or back pain; generalized muscular pain, hypertension, tachycardia, vomiting, nausea, diaphoresis, piloerection, and local erythema
    • Complications: Hypertensive crisis, hemodynamic decompensation with abnormal ECG and elevated troponins, cardiac failure, and death
  • Treatment
    • Antivenom: none
    • Hot water shower as tolerated for 10–20 min
    • Vinegar irrigation
    • Antihypertensive therapy (phentolamine has been used)[1]
    • Magnesium sulfate IV[8]
    • Pain management (including local use of cold packs/ice and opiates)
    • Do not use pressure immobilization bandages

Sea Anemone

  • Taxonomy & Description
    • Many species located in warm waters
    • tentacles loaded with stinging cnidocytes and secrete mucus that may contain cytolytic and hemolytic toxins, neurotoxins, cardiotoxins, and proteinase inhibitors.
  • Symptoms
    • Initially; erythema and pruritus, petechiae, blisters, and ulceration
    • Rare: systemic reactions include fever, chills, malaise, weakness, nausea, vomiting, muscle spasm, and syncope
    • Most cases resolve within 48 hours
    • Severe reactions may become indolent, leading to hyperpigmentation, hypopigmentation, or keloid formation[9]
  • Treatment
    • Acetic acid 5%
    • Symptom management



  • Apparatus that punctures skin, deliver venom
  • Remove stinger, evaluate FB with XR or US
  • Irrigate with hot water for 30-90 minutes
  • Antivenom (stonefish)


  • Taxonomy & Description
    • Family: Dasyatidae
    • Location: tropical warm waters and are found practically all over the world
    • Flat cartilaginous fish with caudal appendages harboring bilaterally retroserrate barbs and associated venom glands
  • Mechanism of injury: 2 phase
    • Mechanical: due to barbed stinger at end of whiplike tail
    • Venomous: gland at the tail base is injected into the victim
    • Venom contains serotonin, 5’-nucleotidase, and phosphodiesterase
    • Toxin may induce peripheral vasoconstriction, bradycardia, tachycardia, atrioventricular block, and seizure activity
  • Symptoms
    • Pain and laceration at puncture site, nausea, vomiting, muscle cramps, barb lodged in skin, pain and swelling
    • Peaks at 60 minutes lasting up to 48 hours.
  • Complications
    • More typically seen if torso injury Hypotension, dysrhythmia, arterial lacerations, thorax, and spinal cord trauma
    • Also nausea, vomiting, muscle cramps, syncope, arrhythmias
    • Cause of death of the late Steve Irwin
  • Treatment
    • Antivenom: none
    • Hot water immersion as tolerated, 30-90 minutes
    • Systemic and local analgesia
    • Plain films to evaluate for FB
    • FB removal- spine, if lodged in chest should be treated like torso laceration and removed in OR
    • If necrosis, area must be debrided
    • Prophylaxis with antibiotics

Spine Fish

Stone Fish

  • Taxonomy & Description
    • Family: Scorpaenidae
    • Most venomous of the scorpion fish, venom comparable to potency of cobra venom
    • Resides in Indopacific ocean
    • 38 cm in length, 1.5 kg
    • Body covered in spines that release venom from mechanical pressure (i.e. someone steps on it)
  • Symptoms
    • Severe pain and edema at site of sting, headaches, Severely painful cyanotic puncture, wound, necrotic ulceration
  • Complications
    • Weakness, syncope, dyspnea, hypotension, and hallucinations, altered mentation, fever, nausea, vomiting, seizures, paralysis, heart block, heart failure, pulmonary edema, death can occur within 6 hours
  • Treatment
    • Antivenom: CSL stonefish antivenom.
    • Remove all spines
    • Hot water immersion as tolerated 30-90 minutes
    • NSAIDs, local analgesia
    • Debridement if needed or deeply penetrated spine
    • Consider prophylaxis with antibiotics
    • Tetanus
    • Observe 6-12 hr

Lionfish and Scoprion Fish

  • Taxonomy & Description
    • Family: Scorpaenidae
    • Location: coastal waters of the Atlantic Ocean (usually Brazil, Uruguay, and Argentina),
    • The scorpion fish remains an understudied fish due to its limited global distribution[10]
    • Toxicity: Stonefish #1, Scorpion Fish #2, Lionfish #3
    • Common cat fish can also cause these symptoms and is statistically more common, although poison is much less severe
  • Symptoms
    • Sharp, intense, throbbing pain at the site of injection which can radiate, peaks at 60-90 minutes
    • Mild: erythema, pallor, ecchymosis or even cyanosis are the first events that present, and result from the increased capillary permeability;
    • Moderate: vesicle formation, as an effect of the toxins;
    • Severe: local necrosis observed within days, which is considered a grave complication and requires debriding
  • Treatment
    • Same as Stonefish
    • Antivenom: none

Sea Urchins

  • Taxonomy & Description
    • Family: Echinodermata
    • Location: global distribution with many different species
    • Globular bodies covered by calcified spines either rounded at the tip or hollow and venom-bearing
    • Apparatus: toxin-coated spines
    • Various urchin venoms have been found to contain steroid glycosides, hemolysins, proteases, serotonin, and cholinergic substances
  • Symptoms
    • Commonly a painful puncture wounds with severe local muscle aching lasting up to 24 hours.
    • Frequently, spines break off into the victim.
    • A spine in a joint can cause synovitis.
    • Systemic symptoms include nausea, vomiting, paresthesias, weakness, abdominal pain, syncope, hypotension, and respiratory distress. Secondary infections are common.
    • Chronic: granulomas may develop
  • Treatment
    • Antivenom: none
    • Hot water (45°C) immersion
    • Wounds irrigated, superficial wounds can be explored
    • Spines “tattoo” the skin so you cant tell if they are out or not


  • Taxonomy & Description
    • Family: Echinodermata
    • Crown-of-thorns starfish (Acanthaster planci) most commonly cited
    • Venom is hemolytic, myonecrotic, hepatotoxic, and anticoagulant
  • Symptoms
    • Puncture wounds with immediate pain, bleeding, and edema.
    • Wounds become dusky and tenosynovitis may develop.
    • Multiple punctures can cause systemic reactions with paresthesias, nausea, vomiting, lymphadenopathy, and paralysis.
    • Pain resolves in 30 minutes to 3 hours.
    • Retained spines can cause granulomas
  • Treatment
    • Antivenom: none
    • Hot water (45°C) immersion
    • Wounds irrigated, explored

Cone Snails

  • Taxonomy & Description
    • Conus geographus
    • Apparatus: venom gland, teeth at end of proboscis (nose)
    • Toxin: conotoxin or neurotoxin that acts as a neuromuscular blockade
    • Blocks potassium and sodium channels, then blocks calcium channels
  • Symptoms
    • Symptoms: Severe pain at site of sting, muscular paralysis
    • Complications: palpebral ptosis, speech difficulty, and swallowing impairment, Respiratory arrest in 40 min to 5 h, duration 12 to 36 hours
    • 50 deaths reported in the literature with mortality rate 25%[11]
  • Treatment
    • Antivenom: none
    • Field management
      • Remove spine if possible to prevent further envenomation
      • Immobilize in hot water 40-45०C for 90 minutes or until pain relief
      • Monitor closely for any evidence of neuromuscular blockade and strongly consider intubation if present
    • Hospital management
      • Maintain ABCs
      • Consider edrophonium for paralysis
      • Consider narcan to reverse hypotension
      • Distal to proximal compression bandage


Blue Ringed Octopus

  • Taxonomy & Description
    • Hapalochlaena lunulata
    • Found in shallow waters throughout Indo-Pacific oceans
    • Injury typically occurs when picked up out of the water by humans
    • Toxicity: venom is tetrodotoxin which inhibits voltage gated sodium channels leading to paralysis
  • Symptoms
    • Symptoms: Flaccid paralysis and hypotension
    • Complications: Respiratory failure and death
  • Treatment
    • Antivenome: none
    • Potentially life threatening exposure
    • Supportive care including mechanical ventilation
    • Elevate affected limb with direct pressure to decrease to minimize spread
    • Complete recovery in 2-4 days

Lizard Bites

  • Taxonomy & Description
    • Family: Helodermatidae
    • Mexican beared lizard found in Mexico and parts of Central America
    • Gila monster found in SE United States
    • Toxicity: venom delivered by bite, delivered by glands in lower jaw
    • Causes localized, rarely systemic effect
    • Note teeth can be left behind in wound as a foreign body and nidus for infection
  • Symptoms
    • Local: crush and puncture wounds, local erythema and pain
    • Systemic: weakness, hypotension, diaphoresis
  • Treatment
    • Antivenom: none
    • Remove animal
    • Imaging to identify FB, especially teeth
    • Irrigate copiously
    • Tetanus
    • Consider antibiotics

Sea Snakes

  • Taxonomy & Description
    • Family: Hydrophiidae
    • Known to inhabit tropical Pacific and Indian oceans
    • Venom: peripheral neurotoxins acting at the acetylcholine receptor, and hemolytic and myotoxic compounds
    • Causes muscle necrosis, hemolysis, and renal tubular damage
    • Approximately 80% of bites do not result in envenomation due to small, easily dislodged fangs
  • Symptoms
    • Initial painless pinhead-sized fang marks
      • Roughly 30-60 minutes later, muscle pain and stiffness, nausea, vomiting, ascending paralysis, respiratory failure, muscle necrosis, renal failure
  • Treatment
    • Antivenom if any symptoms (Mortality rate 3% overall, 25% if not receiving antivenom)
    • Pressure immobilization
    • Maintain airway and breathing
    • Monitor electrolytes and urine output
    • Alkalinize urine if myoglobinuria (NaHCO3, diuretics)
    • Dialysis as needed for renal failure and hyperkalemia



  • General
    • Acellular attach to ocean floor
    • Carry silicon dioxide or calcium carbonate, dermal irritants crinotoxins [14]
    • Species: fire sponge (Tedania ignis), poison bun sponge (Fibularia nolitangere), an red moss sponge (Mammillaria prolifera)
  • Symptoms:
    • Initial: edema, vesiculation, joint swelling, and stiffness typically resolve in 7 days
    • Extensive exposure: fever, chills, malaise, dizziness, nausea, muscle cramps, and formication.
    • Delayed systemic: erythema multiforme or dyshidrotic eczema can be seen
  • Treatment
    • Remove spicules (adhesive tape, rubber cement, facial peel)
    • Apply 5% acetic acid (vinegar) soaks.
    • Steroid cream or an oral antihistamine may provide symptomatic relief.
    • Consider systemic corticosteroids for severe allergy, erythema multiforme, or dyshidrotic eczema.
    • Arrange wound checks because infections may develop requiring antibiotic therapy

Bristle Worm

  • General
    • Covered with chitinous bristles that easily penetrate skin
  • Symptoms
    • Painful urticarial rash last for 2 to 3 days and skin discoloration for up to 10 days
  • Treatment
    • Remove bristles (adhesive tape, rubber cement, facial peel)
    • Acetic acid 5%


  • Both the initial enevenomation and/or antivenom administration can lead to anaphylaxis
  • Anaphylaxis definition:
    • Dermatologic symptoms + 2nd organ system (typically ENT, respiratory or GI)
    • Known allergen + hypotension
  • Signs: hypotension, bronchospasm, facial and airway swelling, pruritus, urticaria, nausea, vomiting, and diarrhea
  • Most occur within 15-30 minutes and resolve within 6 hours.
  • Prevention
    • You can pre-treat with Diphenhydramine
    • Typically 50-100 mg IV in adults and 1 mg/kg in children
  • Antivenom administration
    • Should be given no faster than one vial over 5 minutes
  • If anaphylaxis develops
    • Standard treatment: Epinephrine, Corticosteroids, Antihistamines, symptomatic management and ABCs
    • Administer 0.1- to 0.2-mL aliquots of antivenom should be alternated with 0.03- to 0.1-mg IV doses of epinephrine,
    • Or an epinephrine drip administered, titrating to maintain heart rate less than 150 beats/min

Serum Sickness

  • Can occur secondary to antivenom administration
  • Formation of IgG antibodies in response to antigens in antivenom causes deposition of immune complexes
    • Induces vascular permeability, activate complement, degranulate mast cells, and trigger release of proteolytic enzymes.
  • Symptoms present within 8 to 24 days
    • Includes: fever, arthralgias, malaise, urticaria, lymphadenopathy, rashes, peripheral neuritis, and swollen joints.
  • Management
  • Recommend consultation with specialist

See Also


  1. 1.0 1.1 Fernandez, Isaac, et al. "Encounters with venomous sea-life." The Journal of emergency medicine 40.1 (2011): 103-112.
  2. Meyer, Peter K. "Stingray injuries." Wilderness & environmental medicine 8.1 (1997): 24-28.
  3. White, Julian. "Envenoming and antivenom use in Australia." Toxicon 36.11 (1998): 1483-1492.
  4. Loten, Conrad, et al. "A randomised controlled trial of hot water (45 C) immersion versus ice packs for pain relief in bluebottle stings." Medical journal of Australia 184.7 (2006): 329-333.
  5. Currie, Bart J., and Susan P. Jacups. "Prospective study of Chironex fleckeri and other box jellyfish stings in the “Top End” of Australia's Northern Territory." Medical journal of Australia 183.11-12 (2005): 631-636.
  6. Currie, Bart J. "Clinical toxicology: a tropical Australian perspective." Therapeutic drug monitoring 22.1 (2000): 73-78.
  7. Sutherland SK, Coulter AR, Harris RD. The rationalisation of first-aid measures for elapid snakebite. Lancet 1979; 1: 183-186.
  8. Corkeron, M., P. Pereira, and C. Makrocanis. "Early experience with magnesium administration in Irukandji syndrome." Anaesthesia and intensive care 32.5 (2004): 666-669.
  9. Abdel-Lateff A, Alarif WM, Asfour HZ, et al. Cytotoxic effects of three new metabolites from Red Sea marine sponge, Petrosia sp. Environ Toxicol Pharmacol 2014; 37(3):928–35.
  10. Haddad Jr, V., I. Alves Martins, and H. Minoru Makyama. "Injuries caused by scorpionfishes (Scorpaena plumieri and Scorpaena brasiliensis) in the Southwestern Atlantic Ocean:
  11. Haddad Junior, Vidal, Paula Neto, and Válter José Cobo. "Venomous mollusks: the risks of human accidents by conus snails (gastropoda: conidae) in Brazil." Revista da Sociedade Brasileira de Medicina Tropical 39.5 (2006): 498-500.
Created by:
John Kiel on 14 February 2020 14:59:00
Last edited:
19 February 2020 06:53:32