Should you use vinegar on all jellyfish stings? Does vinegar work for all jellyfish stings? And how does it work?

Everyone has a theory on the best treatment for jellyfish stings - vinegar, hot water, fresh water, urine, cold tea, warm beer.

Queensland experts advise that vinegar is best for jellyfish stings, but not all stingers should be treated the same way, says Dr Lisa-Ann Gershwin, director of the Australian Marine Stinger Advisory Service.

Vinegar works extremely well for box jellyfish and their tiny cousins the irukandji, found northwards along the coast from about where the Queensland town of Bundaberg sits, says Gershwin.

But vinegar should NOT be used for bluebottle stings, found further south along the beaches of eastern Australia. The official advice for bluebottle stings is to gently wash off the stingers with sea water and then immerse the area in hot water (no hotter than the rescuer can comfortably tolerate) for 20 minutes.

What happens when you're stung

We know of 2500 species of jellyfish, and all but one of them has the capacity to sting.

In most cases people don't feel the sting because the harpoon-like stinger can't penetrate the skin or can't penetrate deep enough to be a concern.

Gershwin says all jellyfish use the same delivery systems and triggers. These nematocysts are little capsules filled with coiled up harpoon-like barbs.

"Picture a knife serrated on both edges to help anchor it into its victims flesh when it fires. There's venom on both the inside and outside of the harpoon.

The capsule has a hair trigger, which is fired mechanically by touch. It can also be fired by changes in density or chemistry such as ph differences, or being exposed to fresh rather than salt water.

Although the mechanism is the same, toxins from different types of jellyfish work in different ways , which is why some jellyfish stings are more serious than others. Box jellyfish stings, for example, lock the heart in a contracted state.

"A box jellyfish sting is the worst imaginable pain, says Gershwin. "It is instantaneous and feels like boiling oil."

Irukandji stings, on the other hand, start out as a mild sting but then suddenly cascades 20 to 30 minutes after the sting into the potentally fatal irukandji syndrome - high blood pressure, vomiting, body spasms and profuse sweating.

do jellyfish

Vinegar and tropical stingers

Scientists still don't know why vinegar works for tropical stingers, says Gershwin

"We don't know exactly what's going on chemically, so as to why it works, it's a mystery."

"It's a fluke that we even found out, but it does work and it works better than anything else ever tested."

According to Gershwin vinegar somehow blocks the nematocysts or stinging cells ability to fire, "it happens instantaneously as soon as the vinegar is applied".

"It can't do anything about those that have already fired, but it stops any more from shooting off. In a typical sting you get maybe 10 per cent of nematocysts firing. But on a typical tentacle there will be many thousands that haven't fired off yet."

Rubbing the stingers or pouring fresh water on them, however, should be avoided, as this will cause the nematocysts to fire and make the sting much worse, says Gershwin.

"The last thing you want to do is increase your toxic load if you've already been stung."

Editor's note: since this article was published in 2011, research published in 2014 questions the use of vinegar on box jellyfish stings. The research, published in the journal Diving and Hyperbaric Medicine, suggests vinegar promotes further discharge of venom from already discharged nematocysts.

Hot water and bluebottles

Why hot water instead of vinegar should ease the pain of bluebottle stings is also a mystery, says Gershwin.

"It's the recommended treatment, but remember fresh water will cause nematocysts to fire. On the other hand you are dilating capillaries, forcing toxin to circulate which may be diluting the amount at the sting site.

"Claims hot water denatures the venom have been proven wrong" says Gershwin, "unless the water temperature is at least 60 degrees Celsius. And if you're putting water at that temperature on your skin, you've got bigger problems to deal with.

"In trials, hot water has done a better job than ice at relieving the pain. No one's really sure why, it's not a placebo effect, but it could be blocking pain pathways with another type of stimulus."

http://www.abc.net.au/science/articles/2011/12/13/3389985.htm