Skin bends

[parksie]

A few weeks ago I went on a training trip to a hyperbaric unit, where we were put down to 50m in a chamber. We were told when we came up again that any skin itching was a minor skin bend.

What concerns me is why, if we've come up at the right speed and done all the stops, our skin should manage to get bent?

 

[BillP]

Hi parksie:

The only answer I have is you can do everything "right" and still get the bends. There are no guarantees.

HTH,

Bill

 

[parksie]

Fair enough

So taking all the precautions will minimise the risk in most cases, but anything's possible?

 

[Dr Deco]

Hello parksie:

In the case, “skin bends” is just a term that is applied to the itching. It does not imply any relationship to joint-pain decompression sickness, the real “bends.” Thank goodness.

What occurs when you dive is that dissolved gas is transported to all tissues of you body. When the pressure is then removed, a gas phase (bubbles) can grow in any or all of those tissues depending on the supersaturation of dissolved gas and whether there were any micronuclei present (“seeds”).

Gas bubbles form most readily in adipose (= fat) tissue and muscle tissue. If these two tissue groups that produce most of the gas bubbles detected by Doppler ultrasound bubble detectors. These are not the tissues that produce joint-pain decompression sickness, however. That appears to derive from a gas phase growing in tendons or ligaments (the tissues that connect bones together or muscles to bones, respectively). Just because a gas phase forms, it does not mean that some thing has gone wrong. If one were to prevent all bubble formation (or, more properly, bubble growth), the bottom times would be inordinately short.

In the case of a chamber dive, it is believe that some nitrogen can also diffuse through the skin in addition to being transported through the blood stream. When this occurs, some event of series of events to instigate and an itching sensation develops that persist for about twenty minutes. The itching sensation is thought by some to be initiated by the release of histamine, something akin to a mosquito bite.

Thus, it is not that something has been done inappropriately; it is that tables were developed for in-water decompression and the itching (sometimes called “divers’ fleas”) is a phenomenon in the chamber. I have had these on numerous occasions and you think that you will itch so bad that you will go crazy! :bonk:
___________
Dr. Deco

 

[parksie]

The histamine bit makes sense to me, because I wondered why I didn't itch as much as the others -- I take antihistamines for my hay fever

Good to know it's not serious, though

Thanks a bunch

 

[rcohn]

Dr Deco,

Thus, it is not that something has been done inappropriately; it is that tables were developed for in-water decompression and the itching (sometimes called “divers’ fleas”) is a phenomenon in the chamber.

I'm wondering how this applies to drysuit diving. A large percentage of deep and decompression dives are done in drysuits. I would assume that this skin itching phenomenon would also be a common problem when diving dry, but I haven't heard of this being a problem before. Do you have any comments or data? Have any of the technical divers on the board suffered from this?

Looking forward to your responses.

Ralph

 

[Dr Deco]

Dear rcohn:

You would think that it does apply to drysuits. In truth, I have not heard of any complaints. Possibly, it is also related to skin temperature. Air temperature is always high in short duration chamber dives.

Any other thoughts?

Dr Deco

 

[scubadoc]

Carl Edmonds feels that pruritis is a common manifestation of diving in a compression chamber, most likely due to the release of small bubbles from gas dissolved in the epidermis. In this mild form, no signs are visible, and the itching is temporary, mild, comes and goes and is more marked around the ears, wrists and hands. He does not consider this a systemic manifestation of decompression sickness.

Patchy erythema (Cutis Marmorata), reddish-purple mottled areas can occur, especially around the shoulders and trunk. These are intensely pruritic and are due to a local vascular reaction from bubbles in the tissues below the dermis. This has a more serious connotation and is thought of as a systemic manifestation of decompression sickness.

Blockage of the dermal and subcuticular lymphatics with bubbles usually results in edema and a peculiar pitting of the skin called peau d'orange (French, meaning skin of the orange, or, orange-peeling). This is pigskin appearance more often seen over the trunk of the body and again is evidence of a more serious form of DCS.

Ref:

Edmonds, et al: Medical Aspects of Diving, The Medical Journal Of Australia; 1972, 2:1199-1416