My Arm and a Jellyfish...What the Hell Happened???

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:

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.

I’m surprised it didn’t itch or get painful. I’ve had bad jellyfish stings 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, if that’s possible?

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.

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.

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.

Well, just thank your lucky stars that you weren’t swimming in northern Australia.
Let me introduce the Box Jellyfish

Come and visit anytime…if we don’t kill ya, you’ll have some amazing stories to tell the folks back home!


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

You should read this pleasant little story: The Adventure of the Lion’s Mane, wherein, before the mystery is solved, several people meet this fate:

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.

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?)

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.

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 !

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.

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.

Funnily enough, there are ‘vinegar stations’ every few hundred metres along beaches in FNQ.

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.

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.

Vinegar on jellyfish sting can be deadly: researchers