INTRODUCTION

As a first responder, do you know the up-to-date treatment for a jellyfish sting? In addition, can you apply the treatment steps in the correct order to prevent worsening of the envenomation? It is not surprising that many are confused about the treatment of jellyfish stings, largely due to the perpetuation of anecdotal first aid recommendations and lack of data driven treatments. This review article captures the problem:

“There is much confusion among the public on the first aid protocol for jellyfish envenomation, which is further complicated by the portrayal of quick treatments such as urine and meat tenderizer as suitable therapeutic agents from extrapolated results without discussing the limitations of the findings. There is a great deal of literature on the treatment of jellyfish envenomation, which is contradictive, uncertain and unjustified, and thus reflects knowledge at this time. Anecdotal treatment is accepted due to the scarcity of statistically significant findings of evidence-based medicine. However, many currently accepted anecdotal treatments can exacerbate symptoms.”

This statement helps explain why many reputable medical and home remedy websites are not updated with the most recent first aid recommendations.

BACKGROUND

The two groups of jellyfish most dangerous to humans have historically been in the Indian and Pacific (Indo-Pacific) oceans, but are now increasingly being reported in the Caribbean and South American coasts. They are the Box jellyfish (Chironex fleckeri and other Chironex genus species), and Irukandji jellyfish (Carukai barnesi and Malo genus species among others) whose stings can cause severe systemic effects and death. The Portuguese Man-of-War or Blue Bottle jellyfish (Physalia physalis) are typically found in the Gulf Stream of Northern Atlantic Ocean and in tropical regions of Indio-Pacific oceans. Blue Bottle jellyfish are actually not a true jellyfish but a colonial hydrozoan. They can deliver an extremely painful sting with systemic effects, but rarely cause death. With increasing ocean temperatures and frequent tropical storms occurring in the U.S. East Coast and Gulf Coast there are now frequent annual sightings of Portuguese Man-of-War, and even reported far north in Halifax, Canada during the summer months. Due to the morbidity and mortality associated these three species, most research has focused on treating their stings.

Depending on species, a sting can range from minor skin irritation to excruciating severe pain that may include systemic symptoms including anaphylaxis, cardiorespiratory shock, rapid paralysis and neurogenic shock. The Indo-Pacific Box jellyfish (Chironex fleckeri) is considered to be the most lethal jellyfish worldwide and can cause death within minutes. It is estimated that approximately 100 people die per year (majority in the Philippines) from venom so potent that a single jellyfish contains enough to kill >60 people (Note: Antivenom exists, though its efficacy is controversial). There are additional less lethal Box jellyfish that can be found in Atlantic, Caribbean and Pacific waters, and can also deliver a dangerous and painful sting.

A second group of tiny box jellyfish species collectively known as Irukandji jellyfish (approximately 20 species discovered thus far including Carukai barnesi, Malo, and Carybdea species) are also getting increased notoriety due to life threatening stings that cause Irukandji Syndrome. Named after the Irukandji Indigenous Peoples of Northeastern Australia in which the syndrome was first observed, these potent stings cause massive catecholamine release and present with life threatening hypertension, severe back and abdominal pain, chest pain, vomiting, tachycardia, cardiopulmonary collapse, and death.

Jellyfish tentacles have stinging cells known as cnidocytes that contain penetrating venom organelles known as nematocysts. Each capsule-like nematocyst houses a hollow coiled barbed tubule that is deployed in a dart like manner to inject venom into the victim when triggered. They can be triggered by direct pressure or via chemoreceptor activation. There are potentially hundred thousand or more nematocysts lining the tentacle (based on length), each containing its own tiny trigger and venom apparatus. See an excellent video presentation for all age groups showing a jellyfish sting animation, along with a microscopic slow-motion video of nematocysts injecting venom. Understanding the mechanism of jellyfish envenomation is important as it drives the rationale behind up-to-date medical management recommendations.

The morbidity and mortality related to jellyfish stings has motivated clinical researchers to seek solutions. Research has concentrated primarily on 1) development of improved antivenom, 2) development of topical sting preventatives, and 3) development of more effective first aid treatment algorithms for post sting management. Here we will concentrate on up-to-date evidence based first aid treatment, as antivenom and topical sting preventatives are still controversial areas in need further research. Past treatment recommendations caused much confusion, (e.g., to pee or not to pee; use of ice versus heat application; and to either rub, scrape, shave or pluck). See Table 1 below for a wide range of historic recommendations to manage jellyfish stings, many of which are now known to worsen stings. See Table 2 for common jellyfish myths.

DISCUSSION

In 2017, a Popular Science magazine article titled, You’re Treating Jellyfish Stings All Wrong, provided an excellent overview of the latest jellyfish sting recommendations. Previous sting recommendations had low quality evidence with research suffering from lack of reproducibility and contradictory results. Historically, critical barriers to progress in jellyfish sting research has been the lack of readily available and reproducible envenomation assays, and lack of consensus in field regarding uniform methods for quantifying sting severity and venom load.

Recently however, a series of elegant studies by Drs. Angel A. Yanagihara PhD, and Christie L. Wilcox PhD, from the University of Hawaii and Thomas Doyle PhD, from the National University of Ireland Galway have made great strides. Using tentacles cut from freshly-caught live animals to most accurately reproduce realistic sting events they developed a model that: 1) Exhibits spontaneous tentacle nematocyst discharge; 2) Allows for visualization and quantification of nematocyst discharge; 3) Measures venom load and activity directly; and 4) Employs rigorous controls.

See an excellent interview with Dr. Yanagihara about how her interests began after sustaining a life-threatening sting while swimming at Waikiki Beach. Her sting, and subsequent management by local EMS personnel, lead to her to investigate ways to improve jellyfish sting treatment. She is now the Director of Pacific Cnidarian Research Laboratory; and Founder and President of Alatalab Solutions, LLC, which specializes in venom research, and received funding from the Department of Defense to develop Sting No More™ products for sting treatment of military combat divers. Her team has researched multiple topical solutions to determine what most efficaciously deactivates nematocysts preventing venom injection. Furthermore, an extensive literature review by Drs. Wilcox and Yanagihara concluded that the preponderance of published evidence support the use of hot water immersion and heat application, not ice application, for reducing pain from jellyfish envenomation by denaturing heat labile venom components.

Collectively, Yanagihara and her team have studied multiple jellyfish species across different classes (Box jellyfish species, Portuguese Man-of-War, Lion’s Mane jellyfish, and Sea Nettle among others) with the same laboratory assay techniques, and have shown that these diverse species all respond effectively to vinegar rinse solution followed by heat application. Based on their studies, we now have evidence-based first aid recommendations that apply to different types of jellyfish stings. In addition, they developed a line of Sting No More® products that also show good efficacy as a deactivating rinse solution and topical post sting cream. These products are now commercially available including a spray and cream, and often come with a heat pack for easy application in the field. These products can now help families, lifeguards, and EMS personnel effectively treat jellyfish stings in addition to more traditional household vinegar rinse followed by hot water immersion and topical antihistamine and glucorticoid creams.

Dr. Yanagihara attempts to get the word out about these current recommendations with a one page handout about what to do if you receive a jellyfish sting. This is an excellent resource to help address misinformation, and correctly educate family, friends, colleagues, patients and the public. See Table 3 for a more comprehensive list for up-to-date sting management recommendations. See Table 4 for general jellyfish sting prevention recommendations. Additionally, see these excellent resources for advanced medical care for severe stings, such as Box jellyfish stings and Irukandji syndrome, and treatment of other common marine envenomations in the links contained here.

SUMMARY

Historically, there has been a long tradition of misinformation and myth surrounding jellyfish sting treatment. Recent research across diverse species of jellyfish has established what works, and what doesn’t. In particular it has highlighted which popular home remedies and prior first aid approaches are harmful, leading to additional nematocyst stimulation and venom release worsening the sting. These jellyfish sting recommendations decrease venom load in the tissues with the following threefold approach:

1) Deactivate nematocysts preventing further envenomation: use vinegar (acetic acid 5%) or Sting No More® as the initial 30 second rinse.

2) Decontaminate skin by plucking tentacles from skin with tweezers or gloved hand (do not scrape, shave or rub as pressure and manipulation triggers nematocyst release).

3) Denature injected venom in tissues: immerse the affected skin in hot water (45° C/113° F), hot shower to tolerance or heat pack application for 45 minutes.

These treatment steps now simplify the first aid protocol for jellyfish stings across worldwide. The aim now is to help educate others with these up-to-date recommendations. Therefore, we request a “Call-to-Arms” for all members in the Wilderness Medical Society and from other medical societies, first responders and EMS councils, lifeguard and scuba diving organizations, etc., to education the public, and to update sting management guidelines since we all have the goal to prevent and alleviate pain, and to save lives.

Author (BLB) Comment – the use of full strength vinegar on jellyfish stings from east coast Sea Nettles (Chrysaora quinquecirrha) and Bay Nettles (Chrysaora chesapeakei) has been the primary sting management solution used by York River, Virginia residents, and elsewhere in Coastal Tidewater Virginia, for decades per comments from Katherine M. Bennett, PharmD. She was reared playing in the river with cousins, aunts, uncles, and grandparents, each year since the 1950s, and was stung frequently by an extensive summertime jellyfish presence coming up river from the Atlantic Ocean, and Chesapeake Bay regions.