Unexpected Skin Bends--Why

[chillyinCanada]

Wow! You dive with nitro?!? Surprised you didn’t go BOOM on hitting the water!

Damn autocorrect. . .

 

[Duke Dive Medicine]

I had my Dr. appointment today and here is what I was told.

1. My skin bends were type one and the Doctor said a chamber treatment would have been absolutely unnecessary.
2. He sees divers with skin bends with some regularity (diving in Jupiter is deep, square profile, strong current and, I must say, many divers in the area really push or exceed recreational time depths and limits). He viewed my profiles for the dives in question as "fairly conservative." Most of these divers keep on diving and have occasional recurrences but do not develop more severe DCS.
3. Once you have them, you are more likely to have recurrences. He often sees that divers can dive for months or years and then have recurrences grouped over a fairly short time (month or two depending on how active they keep diving) and then sometimes long periods again without any recurrence.
4. In his view, I can resume diving and continue even if I have an occasional recurrence. I asked him about waiting 4 to 6 weeks.and he said this was not needed. Obviously, he also agreed that if they recurred I should monitor my self for other more serious DCS symptoms, but he said a trip to the ER for O2 would be unnecessary if there were no other symptoms and they resolved within 24-48 hours. He also said that if they keep recurring on every dive trip that more follow up would be prudent, but the occasional recurrence should not be a cause for concern apart from monitoring for other symptoms.

We then had a general discussion about skin bends, which I found interesting and will put the major points here. I am not vouching for whether he is right or wrong, but I thought offering this information would be valuable for discussion and comment.

1. He says there is not a clear causal connection between skin bends and more serious DCS. While they have a common causitive factor (depth, ongassing, then offgassing), most cases of skin bends do not show more serious DCS, and most cases of serious DCS do not show skin bends. He believes that are different types of mechanisms going on in the skin tissues than in the other tissues affected by serious DCS, and that skin bends are nitrogen working its way out through the skin directly as opposed to internal bubbling, but he said little is understood about the precise mechanism and this was his theory based on a review of studies and not a proven fact. He said he has seen one case where a chamber treatment made the mild skin bends worse as (he believed) the nitrogen worked its way out through the skin even faster in a pure O2 environment, which indicated to him type 1 skin binds was not necessarily connected to offgassing through the respiratory system.

2. He does not see the need for the 4-6 week waiting period with type 1 skin bends and no symptoms of more serious DCS. He thinks that severe DCS injures tissues in a fundamentally different way, which makes the long waiting period justified in that case.

3. I asked about more conservatism, longer safety stops, and O2 at the safety stops. He said that there is no evidence that these make any decisive difference on skin bends (they do for more serious DCS, he said). I could dive the computer/table limits and not have skin bends for months or years, or be conservative and still have them, and they could still stop appearing and not recur for a long time either way, or could keep appearing either way. I could have recurrences throughout my life and never develop more serious DCS. Obviously, he agreed that more conservatism would not hurt, but he said there was no guarantee it would help, either, for the type of skin bends I had. Apparently his experience with divers getting type 1 skin bends with some regularity and continuing diving with no other more serious DCS issues has led him to believe that this type of skin bends does not pose, by itself, a serious threat (I am making an assumption here, but this seemed to be the view, which is based on more aggressive divers in this part of the State).

Anyway, my plan is:

1. Wait another month, just in case, give my skin time to recover.
2. Start with a shallower profile
3. When i do a deeper profile (deeper than 50'), go to a more conservative computer setting.
4. See what happens before I take any other measures.

Like most things about diving related illness, there is still a lot that is unknown (as the Doctor was clear to say) . . . .

Guy, thanks for the detailed report. Of course the practitioner who evaluated you in person is in the best position to offer advice. My recommendation to wait 4-6 weeks was because you'd had back-to-back episodes of unexplained DCS. Two weeks may be perfectly adequate. Interestingly, Strauss et. al. recommend a thorough cardiology and neuro work up along with a test dive in a chamber for an individual with multiple incidents of disordering events/disordered decompression before returning to diving. I anticipate some debate about these recommendations.

Type I skin bends is kind of a funky thing and I agree that we definitely don't know all there is to know about them (or any type of DCS). Type I skin bends are not associated with more severe symptoms. Absent any other symptom, it's very benign and we wouldn't treat it in the chamber unless the rash didn't resolve on surface O2. We've seen it in very mild chamber exposures, and there are definitely people who are predisposed to it. Type II bends are associated with more severe symptoms although they themselves are not considered to be severe DCS. Type II bends is more an indicator of considerable decompression stress and possible bubble shunting, so a diver with a type II skin rash (cutis marmorata) needs a careful evaluation by a trained diving medicine specialist. Some practitioners (@Dr Simon Mitchell notable among them) don't treat isolated type II skin bends/cutis marmorata in the chamber either. We'd probably err on the side of caution and treat it, though the thought process is continually evolving.

Best regards,
DDM

 

[MaxBottomtime]

When Merry used to get hers it always appeared as she called it her "itchy patch" in the same area on her upper left arm. Leaving the bottom with several minutes of ndl and making a ten minute safety stop has resolved her issue.

 

[islanddream]

Thanks for talking about your skin bends, MaxBottomtime. My case was a Type II skin bends and I was in the chamber (Cozumel) for about 5 hours. I was told to take 6 months off of diving, and I did. (Dang, I paid for the ScubaBoard trip to Bonaire in January of this year and only got to wave at the boat as it left the harbor!) I've been back in the water since March 24 of this year with quite a few dives (most in Jupiter and about 12 in St. Lucia), and I've extended my safety stop from 3 minutes to 5 minutes. I ascend very slowly to my stop. I watch my computer carefully (got a new computer because I think my computer I was using when I got bent was not accurate...it recently got put out to pasture) and don't get close to deco. (I've always been a conservative diver.) So far, so good. I really think the chamber ride and the extended time off from diving were helpful in my case.

 

[Dr Simon Mitchell]

Some practitioners (@Dr Simon Mitchell notable among them) don't treat isolated type II skin bends/cutis marmorata in the chamber either. We'd probably err on the side of caution and treat it, though the thought process is continually evolving.

Best regards,
DDM

Hi DDM,

Just to clarify, my position is a little more nuanced and confluent with the consensus guidelines published in DHM earlier this year (and uploaded with this message). So, if I saw a diver with isolated cutis marmorata at a location with ready access to recompression I would offer the diver recompression treatment. However, if I was at Bikini Atoll with a diver exhibiting isolated cutis marmorata (in other words, a careful examination had excluded other symptoms and signs), and accessing recompression would involve steaming back to Kwajalein over more than a day and probably an air evacuation from there, then provided I was truly happy that the rash was indeed isolated then I would be comfortable managing the diver with decompression sickness first aid measures only as you suggest.

The principle reason for recompressing a case of cutis marmorata if recompression is easily available is that the symptoms might resolve more quickly and it would reduce the likelihood of any other symptoms developing (and the need to be watching for them diligently over the next 24 hours). The rash itself is not going to harm the patient if it is not treated and when accessing recompression is very difficult (and potentially hazardous) then not recompressing but monitoring the patient for emergence of other symptoms is justified.

Simon M

 

[Duke Dive Medicine]

Thanks for clarifying Simon, and thanks for the reference.

For all, it's worth adding that the Strauss papers mentioned previously have already generated considerable discussion and not a little disagreement in the diving medicine community. As with any theory, it will probably evolve with time and may disappear if confronted with enough contrary evidence.

Best regards,
DDM

 

[Lorenzoid]

. . .
Painful deep pink rash over my abdomen (and around my side) that feels like bruising and showing up about 3 hours after the dives. . . .

This caught my attention, as on a liveaboard trip a few months ago my wife developed what looked like a faint rash on her abdomen (and nowhere else), and with the cruise director's assistance we immediately phoned DAN Australia. DAN was unequivocal that skin bends on the abdomen are essentially unheard of. Based only on that, DAN seemed almost certain it was not skin bends. This was surprising to us, but we felt we had learned something. Could DAN be wrong? We did not misunderstand--that is what DAN said in plain English. All they had to hear was that it was just on her abdomen, and they immediately dismissed the likelihood of skin bends.

 

[Dr Simon Mitchell]

This caught my attention, as on a liveaboard trip a few months ago my wife developed what looked like a faint rash on her abdomen (and nowhere else), and with the cruise director's assistance we immediately phoned DAN Australia. DAN was unequivocal that skin bends on the abdomen are essentially unheard of. Based only on that, DAN seemed almost certain it was not skin bends. This was surprising to us, but we felt we had learned something. Could DAN be wrong? We did not misunderstand--that is what DAN said in plain English. All they had to hear was that it was just on her abdomen, and they immediately dismissed the likelihood of skin bends.

Hi Lorenzoid

If that is what they said they are wrong. The abdomen is the most common place for skin bends in my relatively extensive experience. This does not mean that the rash you saw definitely was DCS, but it certainly occurs in that location.

Simon M

 

[Lorenzoid]

Hi Lorenzoid

If that is what they said they are wrong. The abdomen is the most common place for skin bends in my relatively extensive experience. This does not mean that the rash you saw definitely was DCS, but it certainly occurs in that location.

Simon M

From now having done a little Googling, I can see you're right. That is bizarre. My wife and I as well as the cruise director all heard the DAN Australia guy almost immediately dismiss a diagnosis of skin bends when he heard that the rash was on her abdomen only. Of course, he didn't say "impossible" but he did say something along the lines of very unlikely.

 

[Diver0001]

1. He says there is not a clear causal connection between skin bends and more serious DCS.

I'm glad I stumbled on this. In my technical training my instructor clearly stated that skin bends is *usually* a sign of a severe hit. Maybe I misunderstood it. Maybe what I was being told is that if a diver gets a severe hit then then skin bends are usually part of it.

I may have turned it around in my mind from (A -> B) -> (B -> A), which is clearly an illogical proposition. During my initial training in 1984 my instructor was clear that this was not the case but I'm pretty sure that there is some confusion about the issue out there that even exists at the level of technical instructors.

R..