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Poisonous animals
Cnidarians (Jellyfish, Corals and Anemones)
Venomous fish
Hymenopterans (Bees, Wasps and Ants)
Sea snakes
Terrestrial snakes
Miscellaneous animals

Diagnosis & Treatment — Hospital


General problems

At particular risk are: children, elderly people, patients with pre-existing conditions, such as coronary heart disease, arterial hypertension, lung disease, kidney disease, allergies (sensitisation) and patients taking particular drugs, such as beta-blockers.

Is it likely that a clinically relevant injection of venom has taken place?

D  Diagnostics

Inquire re:

  • time of the sting,
  • local pain,
  • muscle pain, in particular back pain.


  • state of consciousness.


  • blood pressure/pulse,
  • breathing (respiratory rate).


  • the sting itself ("prints", which may enable differentiation of the cause Fig. 4.11).
  • extent of the sting (important for the distinction between "minor stings" and "major stings" in Chironex fleckeri and Chiropsalmus quadrigatus envenoming).
  • Eyes: conjunctivitis, corneal lesions.
  • Clinical signs of regional vascular insufficiency distal to a sting on the extremities.
  • Clinical signs of mononeuritis multiplex distal to a sting on the extremities.
  • Respiratory insufficiency/respiratory failure.
  • Clinical signs of shock (cardiogenic shock, anaphylactic shock).
C  Comments

With one exception, systemic signs of envenoming following cnidarian stings occur more or less immediately after the sting. Carukia barnesi causes the so-called "Irukandji syndrome", which manifests itself after a delay of a number of hours after an initially harmless local reaction.

Emergency medical treatment

S  Signs & Symptoms

Clinical signs of anaphylactic shock.

T  Treatment

Treatment of the anaphylactic shock.

S  Signs & Symptoms

Clinical signs of progressive toxin-related cardiopulmonary failure.

T  Treatment
  • Treatment of the respiratory insufficiency/respiratory failure.
  • Treatment of the cardiovascular insufficiency/cardiovascular failure.
  • → Antivenom (Chironex fleckeri/Chiropsalmus quadrigatus).
C  Comments

Independent of the aetiology, common to all serious cnidarian stings is the possibility that a critical, life-threatening situation may arise within a very short time following the sting. As such there are limits to the formal medical care of such accidents. One strategy to solve this problem is to train paramedics in the initial treatment of cnidarian stings. In principle any cnidarian sting can lead to severe anaphylactic reactions if the patient is already sensitised (Togias et al. 1985). It can be difficult or even impossible to distinguish between anaphylactic shock and toxin-related cardiopulmonary failure (Chironex fleckeri, Pysalia sp.). According to observations to date, however, the severe cases of envenoming with Chironex fleckeri stings appear to have all been toxin-related.

In cases of toxin-related envenoming with respiratory and cardiovascular disturbances, it is important to determine the causative species insofar as different types of envenoming have now been classified, in which relatively well-proven treatment schemes can be applied:

  • Chironex fleckeri stings (see below),
  • Physalia sp. stings (see below),
  • Carukia barnesi stings (see below).

Cnidarian venoms are (thermo-)labile. At body temperature they lose their activity. Thus even if specific treatment, e.g. antivenom, fails, the patient may still be rescued with sustained resuscitation efforts.

Autopharmacological effects

S  Signs & Symptoms
  • Nausea, vomiting, abdominal pain, diarrhoea,
  • urtitcaria, angio-oedema,
  • bronchospasm,
  • arterial hypotension, shock (cause: systemic allergic reactions).
D  Diagnostics


In the case of anaphylactic shock:

  • ECG,
  • blood pressure, pulse,
  • central venous pressure,
  • blood gases.
T  Treatment

Treatment of allergic reactions including anaphylactic shock.

C  Comments

With regard to aetiology, these are primarily IgE-mediated anaphylactic reactions (type I hypersensitivity), i.e. the patient must have already been sensitised.

Cnidarians that cause autopharmacological effects

In principle all cnidarians.

Local effects

Local effects: skin

S  Signs & Symptoms
  • Acute (within minutes), painful linear or blotchy urticarial or papulovesicular skin lesions,
  • erythema,
  • (necrosis, ulceration).
D  Diagnostics


  • assessment of the wound according to the usual criteria,
  • evaluation of the extent of the swelling,
  • long-term: observation for the formation of necrosis.
T  Treatment
  • Inactivation of the nematocysts.
  • Pain management: see also below for  "Chironex fleckeri stings", "Physalia sp. stings", "Carukia barnesi stings"); antivenom for Chironex fleckeri/Chiropsalmus quadrigatus stings.
  • Cleaning, disinfection and dressing of the wound at regular intervals.
  • Tetanus prophylaxis.
  • Immobilisation of the extremity with a splint. Padding and monitoring to prevent pressure necrosis and disturbance of the blood circulation if the oedema increases.
  • Possibly antibiotic treatment (see "Chironex fleckeri stings" below).
C  Comments

Skin lesions that appear immediately following the sting are toxin-induced, in contrast to delayed or recurrent lesions (see below) (Burnett and Calton 1987, Fisher 1987, Kingston and Southcott 1960, Letot et al. 1990, Strutton and Lumley 1988).

Cnidarians that cause local effects on the skin

Aurelia sp., Carukia barnesi, Carybdea sp., Chironex fleckeri, Chiropsalmus quadrigatus, Chrysaora sp., Cyanea sp., Gonionemus sp., Linuche sp., "Morbakka" (Tamoya virulenta?), Pelagia sp., Physalia sp., Rhizostoma sp., Stomolophus sp., Tamoya sp. and other cnidarians.

Local effects: acute regional vascular insufficiency in the affected extremity

S  Signs & Symptoms
  • Peripheral pulse weak or absent,
  • impaired sensation,
  • muscle weakness,
  • cyanosis in the part of the extremity distal to the sting.
D  Diagnostics
  • Doppler,
  • angiography,
  • EMG,
  • measurement of compartment pressure.
T  Treatment
  • Rehydration,
  • oxygen,
  • analgesics,
  • antivenom (see "Chironex fleckeri "stings below),
  • anti-coagulation,
  • direct vasodilators,
  • platelet aggregation inhibitors,
  • reversible regional sympathetic block.

If conservative treatment is not successful: surgical intervention (Williamson et al. 1988).

C  Comments

To date there have only been a few cases of regional vascular insufficiency described (Abu-Nema et al. 1988, Adiga 1984, Drury et al. 1980, Williamson et al. 1988). Neither the pathogenic mechanism nor the optimal treatment have been clarified.

Possible pathogenic mechanisms include direct vascular effects, direct neurogenic effects, stimulation of the sympathetic reflex arc or a combination of these mechanisms (Williamson et al. 1988).

Cnidarians that cause acute regional vascular insufficiency

To date it has been observed following Physalia sp.(?) and Chrysaora quinquecirrha(?) stings.

Local effects: mononeuritis multiplex

S  Signs & Symptoms

Distal to the sting on the affected extremity:

  • impaired sensation, including loss of sensation,
  • muscle weakness.
D  Diagnostics
  • Clinical,
  • EMG.
T  Treatment


C  Comments

To date only a few such isolated cases have been described (Filling-Katz 1984, Laing and Harrison 1991, Peel and Kandler 1990). In all cases there was complete recovery, although this did take as long as up to 10 months (Peel and Kandler 1990).

Cnidarians that cause mononeuritis multiplex

In only one case was the causative species identifiable as Chironex fleckeri on the basis of the tentacle "prints" (Laing and Harrison 1990). In all other cases observed to date, it was not known which animal caused the sting.

Local effects: eyes

S  Signs & Symptoms
  • Pain,
  • conjunctival congestion,
  • chemosis,
  • corneal oedema,
  • iridocyclitis.
D  Diagnostics
  • Clinical,
  • split lamp,
  • intraocular pressure measurement.
T  Treatment
  • Topical corticosteroid treatment and initially cycloplegia;
  • topical beta-blockers and systemic carbonic anhydrase inhibitors if intraocular pressure is increased;
  • if necessary: local antibiotic.

(Glasser et al. 1992).

C  Comments

Most stings affecting the eyes described to date were painful injuries with conjunctival congestion, chemosis, corneal oedema and mild iridocyclitis that resolved on their own or with local treatment within 48 h. However, there have also been reports of iritis, chronic unilateral glaucoma, mydriasis, accommodation disturbances, peripheral anterior synechia, iris depigmentation and blurred vision (Glasser et al. 1992, 1993, Mitchell 1962, Rapoza et al. 1986, Wong and Matoba 1985).

Cnidarians that cause local effects in the eyes

Case reports are available for Chrysaora quinquecirrha and Cyanea annaskala.

Haemostatic effects

See below: "Physalia sp. stings".

Neurological effects

Neurological and cardiac effects

See below:

  • "Chironex fleckeri/Chiropsalmus quadrigatus stings",
  • "Physalia sp. stings",
  • "Carukia barnesi stings".

Chironex fleckeri/Chiropsalmus quadrigatus stings

S  Signs & Symptoms

Local symptoms: unbearable pain.

Local signs: skin lesions with typical ladder-like "cross-hatching pattern" (Fig. 4.11).

Systemic symptoms: cardiac dysfunction (cardiac dysrhythmias, arterial hypotension), respiratory insufficiency. With "major stings", respiratory and/or cardiovascular failure may occur within minutes.

C  Comments

Definition of a "major sting": decreased consciousness and/or >50% of an extremity affected.

D  Diagnostics
  • Clinical,
  • blood pressure,
  • pulse, heart rate,
  • respiratory rate,
  • clinical signs of poor oxygenation,
  • ECG.
T  Treatment

General measures:

Pain: pethidine 1–2 mg/kg body weight, repeat as needed; antivenom (see below).

Cardiac dysfunction: antivenom administration.
Respiratory insufficiency: endotracheal intubation and artificial respiration, in addition to antivenom administration.
Antivenom: Box jellyfish antivenom (CSL, Parkville, Australia, see MAVIN Antivenom Index).
Antivenom indications:

  • "Major sting";
  • clinical signs of respiratory insufficiency;
  • clinical signs of cardiac dysfunction;
  • pain that cannot be otherwise controlled;
  • if scarring is expected, in particular on areas of skin where this would be cosmetically undesirable.

Initial dose: 1–3 vials i.v.; for severe envenoming, 3 vials initially.

Serum sickness: See Antivenom treatment.

Efficacy: see Biomedical database entry "Chironex fleckeri".

C  Comments

Cnidarian venoms are (thermo-)labile. It is assumed that they lose their activity within 15–20 min after absorption into the tissue or the blood circulation. Thus even if pharmacological /antivenom treatment fail, treatment success may still be possible if there are optimal resuscitation conditions. The patient's condition may deteriorate again after a temporary improvement of the circulatory condition due to renewed mobilisation of venom from the periphery (Williamson et al. 1984b).

In order to be effective, narcotic analgesics must be given at a dose that is only possible if the conditions required for the treatment of respiratory depression are present (Beadnell et al. 1992).

Physalia sp. stings

S  Signs & Symptoms

Local symptoms: pain.

Local signs: linear, urticarial or papular skin lesions (see Fig. 4.11).

Systemic symptoms: cardiac dysfunction (cardiac dysrhythmias, arterial hypotension), respiratory insufficiency, possible respiratory and/or cardiovascular failure within minutes.


D  Diagnostics
  • Clinical,
  • blood pressure,
  • pulse, heart rate,
  • respiratory rate,
  • clinical signs of poor oxygenation,
  • ECG,
  • scleral icterus,
  • laboratory findings consistent with haemolysis,
  • renal function.
T  Treatment

General measures:

Pain: Hot water (45°C) immersion (Australia). Cooling with ice (cold packs or ice in dry plastic bags). Care needs to be taken that no ice burns are caused (For Australia see Australian Resuscitation Council website: Guideline 9.4.5 Envenomation - Jellyfish Stings).

Respiratory insufficiency: endotracheal intubation and artificial respiration.

Renal failure: dialysis.

see Biomedical database entry "Physalia spp.".

C  Comments

See the Comments above on "Chironex fleckeri/Chiropsalmus quadrigatus stings". There is no antivenom available for Physalia sp.

Carukia barnesi stings ("Irukandji syndrome")

S  Signs & Symptoms

Local symptoms: pain, may be minimal.

Local findings: local erythema that may be minimal.

Systemic symptoms (may appear after a delay of up to hours!): cramping abdominal pain, back pain, limb pain (nature of the pain: wave-like), vomiting, peripheral cyanosis, oliguria, anxiety, tachycardia, cardiac arrhythmias, arterial hypertension, pulmonary oedema (cardiogenic/non-cardiogenic), heart failure.

D  Diagnostics
  • Clinical,
  • blood pressure,
  • pulse, heart rate,
  • respiratory rate,
  • clinical signs of poor oxygenation,
  • ECG,
  • chest X-ray,
  • echocardiography,
  • intra-cardiac pressure measurement.
T  Treatment

General measures:


Narcotic analgesia is required in severe cases, but no single agent has been universally approved. There are theoretical reasons to avoid pethidine (Bailey et al 2003).

Arterial hypertension: Phentolamine has been used, but may not be available in emergency departments. An agent with a shorter half-life may be preferable (glyceryl trinitrate) given the potential for cardiovascular collapse.  Caution should be exercised to avoid life-threatening hypotension as cases of echocardiographically proven cardiac dysfuncton have occured (Bailey et al 2003).
Pulmonary oedema: Pulmonary oedema is treated in the usual manner (Bailey et al 2003).

see Comments below.

C  Comments

Symptoms of envenoming that are reminiscent of a mild form of "Irukandji syndrome" have been observed following "Morbakka" (Tamoya virulenta), Tamoya sp. and Gonionemus oshoro stings (Fenner 1991, Otsuru et al. 1974). Stomolophus sp. stings are also said to cause an "Irukandji-like" syndrome (Mingliang and Shide 1990) and possibly other species.


The evdence base for treating  "Irukandji syndrome" is anecdotal. It was developed in Australia and employed for the treatment of a number of patients (Bailey et al 2003, Fenner and Hadok 2002, Fenner et al. 1986a, 1986b, 1988, Martin and Audley 1990).

Wounds, in particular necrosis

D  Diagnostics
  • Clinical,
  • bacterial smears.
T  Treatment

Wound care.

Long-term sequelae
1. Keloid

D  Diagnostics


T  Treatment

As with keloids from other causes this is not a rewarding condition to treat.

2. Hyperpigmentation

D  Diagnostics


T  Treatment

Topical hydroquinone 1.8% (Burnett and Calton 1987a, Kokelj and Burnett 1990).

3. Delayed skin symptoms that may persist for months

D  Diagnostics


T  Treatment

No proven treatment available.

4. Recurrent pruritic skin symptoms, onset 4–30 days after the sting, duration of each episode 1–7 days, several episodes possible, episodes may be accompanied by diarrhoea

D  Diagnostics


T  Treatment

No proven treatment available.

C  Comments

There are numerous case reports and some studies on delayed and recurrent skin symptoms following jellyfish stings (Auerbach and Hays 1987, Burnett and Calton 1985, Burnett et al. 1987a, Letot et al. 1990, Mansson et al. 1985, Matusow 1980, Ohtaki et al. 1986, 1990, O'Reilly et al 2001, Piérard et al. 1990, Reed et al. 1984).

Recurrent skin symptoms following jellyfish stings can present a differential diagnostic problem, in particular if they appear after a long delay and if the patient does not remember the sting or the doctor failed to enquire about it.

With regard to aetiology, it is assumed that this is a type IV hypersensitivity reaction. Two different histological forms have been observed:

  • contact dermatitis-like skin reactions (Ohtaki et al. 1990),
  • skin reactions of a granulomatous nature (Reed et al. 1984).

Auerbach and Hays (1987) observed erythema nodosum with arthralgia and fever following a Physalia physalis sting.


S  Signs & Symptoms

Severe allergic reactions including anaphylactic shock following a further jellyfish sting once sensitisation has occurred.

D  Diagnostics
  • Patient history,
  • detection of specific IgE,
  • skin test.
T  Treatment
  • Prevention: avoidance of further stings (see also "General information on cnidarians: Prevention").
  • If the patient finds it an unacceptable restriction to try to avoid further stings: 'Stinger suits' and carrying adrenaline for self-injection; possibly taking H1- and H2-antihistamines before swimming in water where cnidarians are likely to be found (Stein et al. 1989).
C  Comments

Immunological investigations suggest that it is possible for sensitisation to cnidarians to occur (Burnett and Calton 1987). A case study suggests the same (Togias et al. 1985). On the basis of these observations it is assumed that in patients who develop marked allergic reactions, e.g. angio-oedema, following a cnidarian sting there is a risk of a severe anaphylactic reaction following a further sting. There is cross-reactivity between different cnidarian species (Russo et al. 1983).

This risk can be assessed by detection of specific IgE antibodies and skin tests.