What marine life offshore North Carolina can cause histaminic reaction?

July 25, 2014 9:27 AM

My daughter felt something solid while swimming on a North Carolina beach this morning (July 25) and now has a raised welt about 2.5 x 4 cm with a somewhat larger reddish area around it. It is mildly painful. There are no visible foreign bodies, stingers, etc. What could it be? She doesn't seem to be having any severe symptoms that would require an emergency room visit.
posted by dhnyny to Health & Fitness (10 answers total)

Brushed up on a Man O War?

From the site, sometimes a dead bit can even do it.

Detached tentacles and dead specimens (including those that wash up on shore) can sting just as painfully as the live organism in the water and may remain potent for hours or even days after the death of the organism or the detachment of the tentacle.[13]

Stings usually cause severe pain to humans, leaving whip-like, red welts on the skin that normally last two or three days after the initial sting, though the pain should subside after about an hour.

posted by Buttons Bellbottom at 9:31 AM on July 25, 2014 [1 favorite]

There are jellyfish in the water offshore North Carolina. On preview, as Buttons Bellbottom says.
posted by treehorn+bunny at 9:31 AM on July 25, 2014

Sounds like a jelly fish sting. Tell her to try pissing on it.
posted by oceanjesse at 9:41 AM on July 25, 2014

Using urine on Jellyfish stings is an old wives' tale, please don't do that.
posted by Maude_the_destroyer at 9:55 AM on July 25, 2014 [9 favorites]

Response by poster: Jellyfish sting was my first guess but the welt doesn't look anything like online images of jellyfish stings. No barbs, nothing whip-like, just a raised oval. Looks more like an enormous mosquito bite than anything else. Anyway, it seems to be fading after a dose of diphenhydramine and a bath. No longer painful.

Thanks for the replies.
posted by dhnyny at 9:56 AM on July 25, 2014

For future reference, this page is helpful:

http://www.ncpoisoncenter.org/body.cfm?id=284

I've been using something called SafeSea which claims to be a jellyfish repellent (as well as a sunscreen) for my annual Outer Banks vacation. I have no idea if it has been effective except to say that I haven't been stung even in years where getting out to the sandbar was a game of Frogger with jellyfish instead of cars.
posted by ereshkigal45 at 11:09 AM on July 25, 2014 [1 favorite]

(Sorry about the pee misinformation, it's something I was taught as a young scout.)
posted by oceanjesse at 11:49 AM on July 25, 2014

Sounds like a jellyfish sting. I've had a lot of them (mild ones) and you don't need barbs (the "barb" are too small to see). Near the shore the wave action can actually break up the jellyfish so there are little bits of stinging things in a stinging soupy marine mess.

It should go away in a day or two.
posted by KokuRyu at 1:19 PM on July 25, 2014 [1 favorite]

Agreed - there doesn't have to be a barb or a whip pattern for it to be a sting (I do speak from personal experience). Glad she's feeling better.
posted by treehorn+bunny at 3:28 PM on July 25, 2014

It doesn't have to be a jellyfish sting. in fact, it probably isn't, as jellyfish are not nearly so numerous as the anecdotes here might suggest.

Hydroids, anemones, some coral will cause a welt if you step on it or brush too close to it. This page might help you and your daughter identify what she felt. It mostly deals with the marine life found in Florida, but you are going to find much of the same up in North Carolina waters, too.
posted by misha at 7:17 PM on July 25, 2014 [1 favorite]