# My Arm and a Jellyfish...What the Hell Happened??? **URL:** \ **Category:** Factual Questions\ **Created:** [June 24, 2014, 4:38am UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514 "2014-06-24T04:38:31Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Suicide](https://avatars.discourse-cdn.com/v4/letter/s/ccd318/32.png) [@Suicide](https://boards.straightdope.com/u/Suicide)\ **Post date:** [June 24, 2014, 4:38am UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/1 "2014-06-24T04:38:31Z")
I was in Florida last month. I went to the beach one day, there were lots of jellyfish washed up on the beach, I don’t know whether they were dead or alive, they were all puffed up so I assume they were alive and just beached. Anyway, when the jellyfish get too bad, I mean lots in the water near the shoreline, they close the beach, but they didn’t close the beach on this day so apparently it wasn’t deemed a bad jellyfish day. I went swimming for about an hour and didn’t see any jellyfish in the water and nothing out of the ordinary happened… Or so I thought… The next morning when I woke up my right arm was a solid bright red color from my wrist to my shoulder, at first I thought it was sunburn but it was some kind of rash. It didn’t hurt at all and it didn’t itch, there was no pain or discomfort, so I decided I didn’t immediately need to go to a doctor…A few days later, the rash had completely disappeared and there was never any discomfort. I think I might have been stung by a jellyfish while swimming and that’s what caused the rash, but I never saw any in the water and more importantly I never felt any sting or pain or anything like that while swimming, and from what I understand jellyfish stings are painful. Is it possible I got stung and didn’t know it? I’ve also heard you could get a reaction like I did if you come in contact with jellyfish parts or matter, so maybe my arm was brushed by a piece of a dead jellyfish? Is that true or possible? Any info on jellyfish rashes will be appreciated:cool: ---
**Author:** ![TSBG](https://avatars.discourse-cdn.com/v4/letter/t/77aa72/32.png) [@TSBG](https://boards.straightdope.com/u/TSBG)\ **Post date:** [June 24, 2014, 4:45am UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/2 "2014-06-24T04:45:33Z")
You probably got stung by one or more stray tentacles, which can sting even when detached from the jelly, and you didn’t notice at the time. This has happened to me off Long Island in NY–loose tentacles got me. I did notice the initial sting though, and saw the things on my arm. Felt like a bee sting. Despite the differences in reaction, perhaps due to different species, I’m guessing that’s what happened to you. ---
**Author:** ![chiroptera](https://avatars.discourse-cdn.com/v4/letter/c/df705f/32.png) [@chiroptera](https://boards.straightdope.com/u/chiroptera)\ **Post date:** [June 24, 2014, 4:48am UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/3 "2014-06-24T04:48:55Z")
I’m surprised it didn’t itch or get painful. I’ve had bad [jellyfish stings](http://www.mayoclinic.org/diseases-conditions/jellyfish-stings/basics/definition/con-20034045) twice and both times they were itchy and the last time part of my arm blistered up something fierce. Perhaps you lack a [histamine response](http://www.ncbi.nlm.nih.gov/pubmed/16354958), if that’s possible? ---
**Author:** ![Mr.Nylock](https://avatars.discourse-cdn.com/v4/letter/m/77aa72/32.png) [@Mr.Nylock](https://boards.straightdope.com/u/Mr.Nylock)\ **Post date:** [June 24, 2014, 4:50am UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/4 "2014-06-24T04:50:26Z")
It’s hard to say, I wouldn’t want to make any rash judgements. More seriously though, I’ve never heard of that kind of reaction myself - usually it’s more like a bunch of lines, not one solid rash. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [June 24, 2014, 5:41am UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/5 "2014-06-24T05:41:10Z")
Many years ago I was living right on the beach on Long Island, and I got stung on my leg. I’d describe it as “streaky” or “mottled,” rather than solid red. It was mildly painful and itchy, but not to the degree others have described. ---
**Author:** ![PurpleClogs](https://avatars.discourse-cdn.com/v4/letter/p/f04885/32.png) [@PurpleClogs](https://boards.straightdope.com/u/PurpleClogs)\ **Post date:** [June 24, 2014, 6:42am UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/6 "2014-06-24T06:42:37Z")
Different species have differing toxic levels, some very mild in fact. A couple years ago, I was sitting in the wet sand right at the water line in the waves of Galveston and got stung on my hip. Never saw the tentacles, but there was no doubt what it was. Luckily it was a real small area but it still hurt like a MF for about 2 hours and was like a bright red welt. It was so painful that we left early. I didn’t know how long it would last or if it was going to get worse. I should have just waited it out. By that night I could barely feel it. The next day it faded completely. A few years before that, same place, I noticed a reddish rash on my ankle where the skin just felt strange there. The shape was very irregular. I suspect that I stood in some ankle deep water next to tentacles from one that wasn’t as strong, so I didn’t notice it until the next day. It wasn’t really painful, just a mild burning or tingle if I touched it. I’ve seen 4 different types of jellyfish there: moon, cabbage, blue buttons (extremely beautiful), and Portuguese man o wars. The one that hurt a lot was probably the pmw. There were a lot of them on the beach that day. ---
**Author:** ![kambuckta](https://avatars.discourse-cdn.com/v4/letter/k/53a042/32.png) [@kambuckta](https://boards.straightdope.com/u/kambuckta)\ **Post date:** [June 24, 2014, 6:58am UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/7 "2014-06-24T06:58:41Z")
Well, just thank your lucky stars that you weren’t swimming in northern Australia. [Let me introduce the Box Jellyfish](http://en.wikipedia.org/wiki/Box_jellyfish) Come and visit anytime…if we don’t kill ya, you’ll have some amazing stories to tell the folks back home! 😃 ---
**Author:** ![Suicide](https://avatars.discourse-cdn.com/v4/letter/s/ccd318/32.png) [@Suicide](https://boards.straightdope.com/u/Suicide)\ **Post date:** [June 24, 2014, 7:40am UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/8 "2014-06-24T07:40:32Z")
if you see a beached, blown up jellyfish on the sand and drop a rock on it and it pops, is there a liquid that flies out from the jf? can that infect you or give you a rash? i saw someone do this right before i went swimming ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [June 24, 2014, 9:10am UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/9 "2014-06-24T09:10:02Z")
You should read this pleasant little story: [The Adventure of the Lion’s Mane](http://ebooks.adelaide.edu.au/d/doyle/arthur_conan/d75ca/chapter9.html), wherein, before the mystery is solved, several people meet _this_ fate: > [@Arthur Conan Doyle](#): > > Fitzroy McPherson was the science master, a fine upstanding young fellow whose life had been crippled by heart trouble following rheumatic fever. He was a natural athlete, however, and excelled in every game which did not throw too great a strain upon him. Summer and winter he went for his swim, and, as I am a swimmer myself, I have often joined him. > > At this moment we saw the man himself. His head showed above the edge of the cliff where the path ends. Then his whole figure appeared at the top, staggering like a drunken man. The next instant he threw up his hands and, with a terrible cry, fell upon his face. Stackhurst and I rushed forward — it may have been fifty yards — and turned him on his back. He was obviously dying. Those glazed sunken eyes and dreadful livid cheeks could mean nothing else. One glimmer of life came into his face for an instant, and he uttered two or three words with an eager air of warning. They were slurred and indistinct, but to my ear the last of them, which burst in a shriek from his lips, were “the Lion’s Mane.” It was utterly irrelevant and unintelligible, and yet I could twist the sound into no other sense. Then he half raised himself from the ground, threw his arms into the air, and fell forward on his side. He was dead. > > My companion was paralyzed by the sudden horror of it, but I, as may well be imagined, had every sense on the alert. And I had need, for it was speedily evident that we were in the presence of an extraordinary case. The man was dressed only in his Burberry overcoat, his trousers, and an unlaced pair of canvas shoes. As he fell over, his Burberry, which had been simply thrown round his shoulders, slipped off, exposing his trunk. We stared at it in amazement. His back was covered with dark red lines as though he had been terribly flogged by a thin wire scourge. The instrument with which this punishment had been inflicted was clearly flexible, for the long, angry weals curved round his shoulders and ribs. There was blood dripping down his chin, for he had bitten through his lower lip in the paroxysm of his agony. His drawn and distorted face told how terrible that agony had been. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [June 24, 2014, 2:30pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/10 "2014-06-24T14:30:01Z")
> [@kambuckta](#): > > Well, just thank your lucky stars that you weren’t swimming in northern Australia. > [Let me introduce the Box Jellyfish](http://en.wikipedia.org/wiki/Box_jellyfish) > > Come and visit anytime…if we don’t kill ya, you’ll have some amazing stories to tell the folks back home! > > 😃 I was stung by a (dead) box jellyfish on arm and hip the day after my tenth birthday. I was liberally doused in vinegar by an alert physician who happened to be at the beach and it saved my life (along with my dad frantically driving me to the hospital, antivenin, antihistamines, and a defibrillator.) I still have a buffalo-shaped scar on my right arm twenty-one years later. It looks a lot like a birthmark. ---
**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\ **Post date:** [June 24, 2014, 2:35pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/11 "2014-06-24T14:35:53Z")
> [@Really\_Not\_All\_That\_Bright](#): > > I was liberally doused in vinegar by an alert physician who happened to be at the beach and it saved my life Happened to be at the beach with a jug of vinegar?? (Glad he was there tho…I assume they keep it around at the beach?) ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [June 24, 2014, 2:40pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/12 "2014-06-24T14:40:45Z")
Once my friend and I figured out what had happened (he was stung as well, but only on his fingertips) we ran screaming to the beach bar/restaurant. It was in Oman and box jellyfish are pretty common there, so most people have at least a vague idea what to do. Bathing beaches are guarded by nets but there was a regatta a half mile offshore and our theory is that the jellyfish was chopped up by a propellor. The resulting bits would have been small enough to fit through the net. ---
**Author:** ![elbows](https://avatars.discourse-cdn.com/v4/letter/e/b3f665/32.png) [@elbows](https://boards.straightdope.com/u/elbows)\ **Post date:** [June 24, 2014, 3:07pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/13 "2014-06-24T15:07:57Z")
Swam into one off the coast of Thailand, round Christmas time. Ouch! It was like a dozen bee stings. Had an uncomfortable night, after that it was pretty much just a couple of big ugly welts that took a couple of months to clear. It looked like blood blisters, but now I just have a couple of scars. Took ages for the big welt to go down. And two weeks before people stopped offering to pee on me. Sorry about your luck, jellyfish suck! The one I ran into was clear as glass and the size of a dinner plate. Hardly seems sporting somehow, but at least it didn’t have long tentacle thingys ! ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [June 24, 2014, 3:08pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/14 "2014-06-24T15:08:12Z")
> [@ZipperJJ](#): > > Happened to be at the beach with a jug of vinegar?? > > (Glad he was there tho…I assume they keep it around at the beach?) It is known that an immediate rinse of vinegar on the affected area will neutralize the sting and prevent further harm. ---
**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\ **Post date:** [June 24, 2014, 3:21pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/15 "2014-06-24T15:21:02Z")
> [@Enola\_Straight](#): > > It is known that an immediate rinse of vinegar on the affected area will neutralize the sting and prevent further harm. Not questioning that one bit. My question was where did the vinegar come from. I’m not doubting his story - I just have no familiarity with beach first aid. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [June 24, 2014, 5:33pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/16 "2014-06-24T17:33:54Z")
If \*\*Suicide \*\*was in Florida and the jellyfish looked puffed up, I’m guessing they were Men o’ War, which are not true jellyfish. I used to see those at Miami Beach all the time. Using vinegar on a man o’ war sting actually makes it worse. My son was stung by what we think was a stray man o’ war tentacle in Hawaii, and his first complaint was that his hand felt numb and tingly, then became painful. The rash was not severe and lasted a couple of days. I am surprised that \*\*Suicide \*\*had such a pronounced redness with no pain or discomfort, regardless of exactly what caused it. ---
**Author:** ![kambuckta](https://avatars.discourse-cdn.com/v4/letter/k/53a042/32.png) [@kambuckta](https://boards.straightdope.com/u/kambuckta)\ **Post date:** [June 24, 2014, 9:02pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/17 "2014-06-24T21:02:00Z")
> [@ZipperJJ](#): > > Not questioning that one bit. My question was where did the vinegar come from. I’m not doubting his story - I just have no familiarity with beach first aid. Funnily enough, there are [‘vinegar stations’](http://www.tripadvisor.com/LocationPhotoDirectLink-g261596-i24193008-Airlie_Beach_Queensland.html) every few hundred metres along beaches in FNQ. ---
**Author:** ![PurpleClogs](https://avatars.discourse-cdn.com/v4/letter/p/f04885/32.png) [@PurpleClogs](https://boards.straightdope.com/u/PurpleClogs)\ **Post date:** [June 24, 2014, 9:06pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/18 "2014-06-24T21:06:58Z")
> [@ZipperJJ](#): > > Happened to be at the beach with a jug of vinegar?? > > (Glad he was there tho…I assume they keep it around at the beach?) Actually, I keep a small thing of vinegar and a bottle of meat tenderizer in a beach bag along with sunscreen, lip balm, band aids, my hat and some other things. I tried it all. Just in case. After I was stung, I did a lot of reading on it and all those things, even urine are just myths, although they do rinse off the tiny tentacles which stops the sting and leads to the misconception that those substances neutralize the sting. In reality, just plain sea water does the same thing. The reason lifeguards perpetuate the myth is that so many people are convinced that’s what should be done that if they just said use seawater people wouldn’t think positive. Mind over matter. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [June 24, 2014, 9:51pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/19 "2014-06-24T21:51:38Z")
It’s not a myth that vinegar neutralizes unfired nematocysts. It does (it doesn’t “neutralize the sting”, though - it’s going to fucking hurt, and nothing you can do will change that.\*) What’s in question now is whether it causes active nematocysts to release additional venom. \*except passing out, which was the method I chose. ---
**Author:** ![Enter\_the\_Flagon](https://avatars.discourse-cdn.com/v4/letter/e/b9bd4f/32.png) [@Enter\_the\_Flagon](https://boards.straightdope.com/u/Enter_the_Flagon)\ **Post date:** [June 24, 2014, 10:26pm UTC](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514/20 "2014-06-24T22:26:38Z")
> [@Really\_Not\_All\_That\_Bright](#): > > It’s not a myth that vinegar neutralizes unfired nematocysts. It does (it doesn’t “neutralize the sting”, though - it’s going to fucking hurt, and nothing you can do will change that.\*) What’s in question now is whether it causes active nematocysts to release additional venom. [Vinegar on jellyfish sting can be deadly: researchers](http://www.smh.com.au/technology/sci-tech/vinegar-on-jellyfish-sting-can-be-deadly-researchers-20140408-zqs8b.html) > [@](#): > > Vinegar may kill rather than cure victims of box jellyfish stings, Queensland researchers have found. > > The remedy, used for decades to treat stings, causes up to 60 per cent more venom from the lethal jellyfish to be discharged into the victim. > > The findings have prompted calls for the Australian Resuscitation Council to revise their sting treatment guidelines. > > Research co-author and venom expert Jamie Seymour says the research changed his mind about vinegar. > > “I thought I’d be able to show the world why you use vinegar,” the James Cook University associate professor said. > > “But what we found was that by using vinegar, what you’re effectively doing is increasing the venom load in the victim.” [Next page](https://boards.straightdope.com/t/my-arm-and-a-jellyfish-what-the-hell-happened/691514.md?page=2)