I have probably experienced almost every possible cause of itching throughout my life. Most of those listed below I have experienced during the last 3 years. This unfortunately has made me somewhat of an expert on itching skin:
Bug Bites (especially of the tropical variety – sand fleas and mosquitos)
Clothing not made from cotton
Residual detergent in my clothes after washing
Fire Coral stings while diving
Muck-diving in waters filled with stinging hydroids — that caused the rash above
Swimming in Chlorinated Pools
Allergies to food
Allergies to Prescription Medicine (ie. Pain pills – not used during the last 3 years)
I have at some point in my life taken almost every type of prescription, over-the-counter, and natural remedy known to man for the alleviation of itching. I have not found any prescription or OTC medicine that works. Most can actually be harmful to you. Few natural remedies that claim they help itching actually work. The rash in the picture above was caused by diving without a wetsuit for protection, with my knees resting in the sandy bottom of the ocean that contained stinging hydroids while taking pictures off an island in Indonesia. This rash caused intense itching and burning. It took 2 weeks to entirely disappear. However, I know how to deal with these things and therefore to be able to keep diving. Welcome back to my world.
When doctors see a rash or skin irritation that they really cannot identify, they call it dermatitis, a rather meaningless word that covers almost anything and makes you the patient feel like you got a proper diagnosis and treatment for your investment in an office visit co-pay or whatever you are lucky to have under Obamacare. The most commonly prescribed treatments involves cortisone, which is a steroid drug and can cause many negative side-effects including headache, nausea, diarrhea, irregular heartbeats, blurred vision, and possible long-term thinning of the skin layers making you even more susceptible to skin problems in the future. So the treatment can cause a lot worse things than your original problem — itching.
An interesting phenomenon that I have discovered is that the body has a certain tolerance level to things that cause itching. However, once you pass a certain threshold level, your body’s reaction will suddenly cause the rash and itching to spread and seem out of control. For example, a couple of sand flea bites on a tropical beach will cause some localized itching. The body’s initial reaction is to cause you to scratch those isolated spots, an automatic response that is designed to remove the foreign item that is sitting on or in the skin that is causing the itch. However, if you have more bites progressively added, or combine the bites with a secondary cause that is coincidently occurring at the same time (ie. athlete’s foot at the same time as having sand flea bites), you can reach that level where suddenly the rash and itching spread throughout your skin and you now have uncontrollable itching.
There are new theories behind this observation. The leading one is that the body increases the secretion of a chemical called histamine that is a natural response to itch-causing stimuli. The histamines are circulating throughout the body in your blood. These histamines can themselves cause more itching. At a certain point, the histamines reach a level in the blood that is high enough to cause the itching to suddenly spread throughout the body. Some doctors call this histamine intolerance. It is also possible that histamine is not the only chemical that the body is releasing in response to these stimuli. However, the end effect is the same — at a certain threshold, these chemicals will spread the itching and the rash throughout the body.
On a recent dive trip, I rested my knees my on the sandy bottom for stability while taking pictures. The microscopic hydroids that live in the sand injected their poison which caused the skin around my knees to immediately swell and itch. Since there was no ammonia on the dive boat, I was forced to use a “natural form” of ammonia (my urine) and apply it to the knees in order to neutralize the hydroids that entered my skin. By itself, the stinging hydroid exposure would have been merely annoying, to one localized area of my skin. However, combined with a few mosquito bites, and the itching and rash spread to my arms, legs, back and chest. I had passed above a certain threshold of tolerance to itching by the combined stimuli.
The only solutions that I have found that work for this extreme itching and which saved this dive trip are:
-Remove and isolate the initial causes of the itching.
-Take frequent very hot showers, which seem to temporarily neutralize the histamines or whatever the chemicals that were building out of control.
-Rub some seaweed powder as a paste onto the initial sites of the bites and stings to help draw out the poisons and also also give some relief to the skin. Do this in the shower for a few minutes allowing the paste to dry. Then rinse off with hot water.
By reducing the continued stimulation from the bites and stings, and reducing the effect of the histamines and other itch-response chemicals in the blood, eventually the threshold drops to a level of tolerance and the rashes that were spreading across the body will reverse. For the initial days after the stings, this will help you to be able to to sleep.
Most divers follow the simple rule of wearing a light wetsuit even in very warm waters to protect their skin from poisonous sea life. I can be stubborn and don’t abide by this rule. I prefer the feeling of freedom of diving in just a bathing suit … and of course run the risk of these sorts of situations occurring. Too many years diving in a bulky wetsuit or drysuit in cold waters have me looking forward to those times where I can dive without one. Notice the sandy bottom around the coral formations in the photo below, which turned out to be the perfect breeding ground for these poisonous hydroids.