(Blue Ocean Network – April 19, 2012) — Has a client complained of a red bumpy itchy rash within a day of being in seawater? And it takes days, sometimes weeks, for it to clear up?  It’s “Sea Itch” time of year in the Caribbean. Also known as “Sea Bather’s Euption”, Sea Itch is an intensely itchy red rash with small blisters, sometimes in clusters and elevated areas of skin which affects the bathing suit-covered – rather than the exposed – areas of the body. Sea Itch usually becomes noticeable between four and 24 hours after exposure.  A tingling sensation under the bathing suit (breasts, groin, cuffs and ankles of wetsuits) is often first noticed while still in the water.nAlthough it can occur at anytime of year, Sea Itch tends to be a seasonal affliction for water goers, with outbreaks occurring intermittently between March and August, and peaking between mid–April and early July.  Sea Itch affects most of the coastal United States, the Gulf of Mexico, the Caribbean islands, Mexico, and South America. It is also present in the Pacific, notably in parts of the Philippines, Thailand and Australia.nWhat Causes Sea Itch:ntThe larvae from Thimble Jellyfish are the culprits of  this annoying itchy rash.   During summer months high concentrations of these stinging larvae may float in “clouds” or “blooms” that affect large areas of beach zones or at the tops of reefs in coastal areas.

They are normally found present within the first 30 feet.nWhen swimming, snorkeling or diving where these tiny larvae are present, the stinging structures surrounding the larvae, called “nematocysts”, get trapped between swimsuit and skin or collect in hair and body creases. The nematocysts “fire” when pressure is applied to them or when they are exposed to a foreign environment such as air or fresh water. The rash is caused by the body’s allergic reaction to the toxin injected into the skin by these tiny stinging cells of the larval jellyfish. nThe resulting Cercarial dermatitis from a larval Thimble Jellyfish sting is very uncomfortable, unsightlly and can last for many days, slowing down if not messing up a carefree dive holiday. The rash typically develops underneath the swim suit, which is believed to trap the jellyfish larvae against the skin. As the swimmer gets out of the sea, water drains out of the bathing suit, trapping the larva between the suit and the skin. Pressure on the small jelly fish cause the stinging cells to discharge, releasing toxin into the skin. Wearing bathing suits for prolonged periods after swimming, showering in fresh water, and mechanical stimulation (rubbing with a towel) make the eruption worse. It appears that snorkelers and swimmers seem to be the most vulnerable to sea itch since the infestation seems to occur near the surface of the water.

What to do About Sea Itch: While it is known what causes Sea Itch rash, there is some speculation as to what to do about it. Here are some standard preventative measures and treatments for Sea Itch Treatment. Generally, dermatitis is the only symptom of Sea Itch. Once the rash occurs (and the swimsuit has been removed and body has been rinsed in sea water that doesn’t contain the larvae), an application of vinegar helps to neutralize any toxin left on the skin. The vinegar rinse should be reapplied to the skin until the itch dissipates. Gently scraping the afflicted area with a dull flat edge such as a credit car or driver’s license removes remaining stinging cells left on the skin.  Some home treatments suggest shaking meat tenderizer over the reddened area and then pouring the vinegar over it, repeating the process until the itching sensation subsides.nThe dermatitis can easily be treated with over the counter medications available from a local pharmacist. Applying a Hydrocortisone cream to the rash areas helps to reduce redness and itching.   Take an oral antihistamine such as Benadryl to soothe the itching, following package directions.

To avoid possible drug interactions do not use Caladryl lotion or any other topical preparation containing diphenhydramine if taking an oral antihistamine.  Following directions, apply over-the-counter topical antibiotic ointments to reduce the chances of secondary infections caused by scratching the rash. An ice pack may also help to relieve any pain. nSea itch can last for as little as 2 days or as long as 2 weeks. Rashes that last longer may indicate a secondary infection. In cases where dermatitis covers a large area of the body and significant swelling is present, or if other side effects occur, see a physician.  A doctor may prescribe prednisone to calm inflamation.  In very rare cases (usually with young children) the patient may experience nausea, vomiting, diarrhea, headache, fever, or muscle spasms. Extreme allergic reactions may require hospitalization.nSince Sea Itch is the body’s allergic reaction to the nematocyst venom, the whole body might break out in a rash, and not just the site of the stings.  To help with healing, stay out of the sun. To avoid secondary infection don’t scratch the afflicted areas. Sea Itch First Aid Product Developed in 2007 by by Webb Willmott, a Florida pharmacist and his wife Julie Willmott, StingMate® is a first aid product that neutralizes jellyfish stings. StingMate® is a 5% acetic acid gel with menthol that comes in a 4oz bottle.

Acetic acid is the active ingredient in vinegar that is responsible for inactivating the stinging cells of jellyfish. StingMate® is much more convenient and practical than bringing a gallon of vinegar on a beach or boat outing.  Stingmate is easily packed in luggage and only a little gel goes a long way.  Another advantage of StingMate® is the gel suspends any remaining stinging cells left on the body by the jellyfish where they can be removed without ‘firing’. After initial application (and waiting at least 2 minutes for the gel to deactivate the larvae), the gel is scraped off with any straight edge card and reapplied, then later rinsed off.nMyths and Misdiagnoses of Sea Itch. ntIt’s important for divers to know the symptoms of Sea Itch so they don’t get a misdiagnosis from the local pharmacy. Sea Itch can erroneously diagnosed as Sun Poisioning, Sand Fleas, Scabies or Sea Lice.nSea Itch is most often misnamed ‘Sea Lice’, which are true crustacean parasites of fish. Sea Lice are flatworm larvae that try to burrow into the swimmer’s skin (so they bite rather than sting) and are usually found on exposed skin (similar to sandflies bites). Another inaccurate perception is that Sea Itch is caused by the larvae from Thimble Jellies “biting” the victim or even burrowing under the skin and growing – neither situation is the case.nAnother myth is the that the topical anaesthetic Lidocaine is the best treatment for Sea Itch. (Lidocaine is the active ingredient in topical hemorrhoid cream Preparation H). It has been found that household vinegar is by far the most effective home remedy for Sea Itch.nPossible Ways to Avoid Sea Itch:ntAccording to experts, not much can be done to completely avoid the larval jellyfish’s sting if the larvae are present in the water.   The larvae are large enough to be visible to the naked eye but become nearly invisible in the water.  Unfortunately the only reliable method of identifying when sea lice are present is by the appearance of the rash on other swimmers or divers.

However, if you see adult thimble jellyfish in the water – they normally float near the surface near shore – avoid them. Don’t swim through them as larvae may be present.nLocal dive professionals claim that covering exposed skin with baby oil or Vaseline will protect against sea itch but often these various creams do not provide a strong enough barrier to the stingers. A full wet suit or dive skin can help to limit the infestation to the edges of the garment.nCommon Preventative Measures for Sea Itch:ntThe most common and effective preventive measure is to take off the swimsuit as soon as possible after exiting the water and rinsing the body in seawater that doesn’t have the jelly fish. Pat-dry with a towel and change into fresh clothes. Do not rub the affected areas with towels or hands as that could cause additional stinging. A note of caution: An immediate rinse with fresh water, especially with the bathing suit on, may actually cause additional stinging from larvae clinging to skin or clothes,nDon’t reuse a swimsuit without careful cleaning, after coming into contact with Sea Itch. Be aware that you can still be stung days or weeks later after washing and drying the infested clothing. The stinging cells are not actually alive and can persist until a particular physical or chemical reaction stimulates them to fire the stinger that contains the toxin.

If a person has developed Sea Bather’s Eruption, the clothing should undergo machine washing or be thoroughly rinsed in alcohol or vinegar, then be washed by hand with soap and water.nJellyfish Repellent Lotion:ntAccording to Dr. Paul Auerbach, an expert on marine envenomization and medical advisor to the Divers Alert Network, one of the most significant advances in jellyfish sting prevention is Safe Sea. Developed by marine biologist Amit Lotan, PhD, Safe Sea is a combination sunblock and jellyfish sting inhibitor. The product was modeled in part on naturally occurring compounds found in clownfish (who live unharmed among stinging anemones) and snails that eat jellyfish. In clinical trials, Safe Sea  successfully blocked the firing mechanisms of a number of jellyfish species. Dermatologist tested, each 4 oz. bottle of Safe Sea contains enough lotion for approximately four full-body applications on an average-sized adult. Each application is good for up to two hours of protection from stings depending on activity level and time spent in the water. A safe guideline is one bottle per adult per day if you’re spending most of your day at the beach. The product should be applied 10 minutes before entering the sea.  Safe Sea is suitable for adults and older children.nA Final Bit on Sea Itch.ntPeople who have had previous exposure to Sea Itch tend to have immediate stinging sensations on re–exposure.  If you feel an itchy tingling on your skin (not to be confused with decompression sickness) or if you see Adult Thimble Jellyfish in the water, get out of the water.  Finally there is evidence to suggest that due to overfishing,  global warming and increases in pollution and resulting”dead zones” in the sea, worldwide jellyfish populations are on the rise: Jellyfish thrive in areas of low oxygen, and dramatically reproduce when environmentally stressed. All the more reason to be prepared for Sea Itch on a dive vacation.

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