rash after scuba diving, what is it?

[gajeep94yj]

Wife and I went to Cozumel last week for the first time. had a blast definitly going back ASAP.

but to my question. both the wife and I have a rash looking thing that sort of looks like poision ivy but doesn't itch. I have it on both of my knees and my wife has it on her forarm. we know what "thing" caused it and i will try to descibe it. it was a black hairy looking twig type thing that was on the sea floor. I know we shouldn't have touched it but we just bumped up against it while looking under cave at sleeping nurse shark. it's the only think we can think of that both of us remember touching. it sort of burned for a second when it was touched but went away quicky.

does anyone know what that "thing" was?

to recap it looks like a small soft twig. it was black about 5"-8" tall, and appeared to be hairy. it stung for a second but quickly went away.

 

[DiveMaven]

Sounds like you had an encounter with Fire Coral.

 

[gajeep94yj]

nope, I know what fire coral looks like. this was black, hairy, and soft.

fire coral is red, hard, and never stops burning

 

[halocline]

Sounds like a gorgonian; was it sessile (attached to something) or mobile? Those "hairs" are nemocysts which are actually little darts (sort of) that the creature fires into whatever touches it, usually tiny plankton which it then digests. Or, if it was mobile, it could have been a bristleworm in which case the hairs are defensive.

 

[TheRedHead]

I believe it is a hydroid and they're all over Cozumel. It is easy for the current to push you and cause you to brush them. I would never wear a shorty in Cozumel.

 

[Diver Lori]

Go to the DAN site and look up the different derm things you can encounter. They list symptoms and also treatments, over the counter and prescription.

I got back from Kona about 3 weeks ago with a nice rash all over my torso which fit the bill of seaweed dermatitis. My local doctor prescribed a week of prednisolone which did the trick nicely....made a huge difference with just the first megadose!

 

[DocVikingo]

Hi mattboy,

It almost certainly wasn't a bristle worm.

gajeep94yj describes a rash on both of his knees and on his wife's forearm from briefly bumping up against "...a black hairy looking twig type thing." First, that would either be one very busy and quick bristle worm or many of them ; ) Second, I have never seen a black one, either live or in photos, nor I am aware of them being reported (at least in CZM).

He also reports, "...it sort of burned for a second when it was touched but went away quicky." This is not at all characteristic of bristle worm envenomation, which typically is described as significant burning pain, occasionally excruciating, that perisists for some period.

BTW, those "hairs" are "nematocysts."

Regards,

DocVikingo

 

[DocVikingo]

Hi gajeep94yj,

I suspect that TheRedHead is correct about it being a stinging hydroid of some type. They indeed are all over Coz, easy to brush up against and hairy/feather-like in appearance. They can look black because of their stalks.

Given contact with them, it is not unusual to experience just brief stinging but develop a red rash that hangs around for a while.

This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual, and should not be construed as such.

Regards,

DocVikingo

 

[halocline]

Thanks for the correction, Doc!

 

[DocVikingo]

Hey mattboy,

F'sure.

But, you raise a good isssue--give bristleworms wide berth. It can can be a nasty envenomation and even standard dive gloves don't provide good protection.

Regards,

DocVikingo