Dealing with Coral and Jellyfish Strings:
When I dive in tropical reef seas, I am careful not to touch the coral, but even so I usually get stung, with red skin, prolonged itching, progressing to blisters, mostly on the fingers, sometimes on the exposed part of my face. The stings may be from coral or jellyfish nematocysts.
For protection, I wear gloves, either scuba or work gloves such as Firm Grip (which cost half the price of scuba gloves). Bare thumb and index finger tips are useful to handle the camera and strobe controls. My hands are fine for a few days, then the stings begin with itching, progressing to skin redness and blisters. The itching and stinging is not under my wetsuit, just in the hands. This past trip I noticed that after a few days of diving, the itching began when I put on the gloves, their cloth was contaminated with stinging venom, so I turned the gloves inside out and washed them with the soap available on the dive boat, namely baby shampoo, with no stinging when I put the gloves back on.
When the itching started, after the dive I lathered my hands with baby shampoo (commonly used to prevent mask fogging) and the itching stopped, with little or no blistering. By then I had two small blisters; twice, when the itching of blisters on my finger was intense, I stuck the finger in hot water (I guess about 60° C) for a few seconds, and found that the itching was promptly relieved.
I lathered my hands with baby shampoo the remaining two weeks of diving, and had no further itching or blistering. The small bottle of shampoo (together with bottles of vinegar and alcohol) I carry in my dive baggie came in handy for this.
It may be that the poison from the nematocyst stingers soak through the fabric of the gloves. I will be interested to hear from other divers who might try this simple approach to sting prevention.
It may be that the toxin stays on the surface of the skin for days, from where it can, and should, be washed off promptly and completely. Some coral and jellyfish toxins are known to be complex fats, which are washed off by detergents (alcohol may solubilize and spread them, so it should not be used). This may explain why baby shampoo or similar detergent has worked for me.
I hope this simple detergent approach will help others prevent the itching redness, itching-burn and blisters of coral stings.
My experience is limited to mild stings. For bad ones, DAN has a webpage:
The treatment of severe stings is outlined by Dr. James L Caruso: http://www.scubadivi...at-coral-stings
These photos show the stings of a fellow diver who was not wearing gloves when he touched the coral.