I was swimming for exercise out in front of my hotel in Cozumel when my entire body started to tingle. I didn't see anything in the water, so I kept swimming. A few minutes later, I swam into a swarm of tiny pulsating brown blobs. They didn't have any tentacles that I could see. The stinging got pretty bad, especially underneath my bathing suit. I hosed off on the beach and jumped in the shower, and that seemed to help. Now I have an ugly red rash under my neck and where my bathing suit goes. I'm having trouble sleeping, and it seems like I'm tired all the time. What should I do?
Often misnamed "sea lice" (which are true crustacean parasites of fish, and which inflict miniscule bites), sea bather's eruption occurs in sea water and involves predominately bathing suit-covered areas of the skin, rather than exposed areas. The skin rash distribution is very similar to that from seaweed dermatitis (read below), but no seaweed is found on the skin.
The cause is stings from the nematocysts (stinging cells) of the larval forms of certain anemones, such as Linuche unguiculata, and from thimble jellyfishes. The injured person may notice a tingling sensation under the bathing suit (breasts, groin, cuffs of wetsuits) while still in the water, which is made much worse if he/she takes a freshwater rinse (shower) while still wearing the suit. The rash usually consists of red bumps, which may become dense and confluent. Itching is severe and may become painful.
Treatment consists of immediate (for decontamination) application of vinegar or rubbing alcohol, although the relief may be minimal. Some persons note that topical papain (e.g., unseasoned meat tenderizer) and simultaneous brisk rubbing are effective. Others have noted relief from concentrated citrus (e.g., lime) juice applied to the skin. Topical calamine lotion with 1 percent menthol may be soothing. After decontamination, hydrocortisone lotion 1 percent twice a day may be minimally effective. More potent topical steroid preparations or oral prednisone may be prescribed by a physician to provide sufficient anti-inflammatory effect to quell the reaction somewhat. However, it is not uncommon for a patient to be miserable for a few days to two weeks.
If the reaction is severe, the injured person may suffer from headache, fever, chills, weakness, vomiting, itchy eyes and burning on urination, and should be treated with oral prednisone. The stinging cells may remain in the bathing suit even after it dries, so once a person has sustained 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.
Sea bather's eruption is easy to confuse with "seaweed dermatitis." There are more than 3,000 species of algae, which range in size from 1 micron to 100 meters in length. The blue-green algae, Microcoleus lyngbyaceus, is a fine, hair-like plant that gets inside the bathing suit of the unwary aquanaut in Hawaii and Florida waters, particularly during the summer months. Usually, skin under the suit remains in moist contact with the algae (the other skin dries or is rinsed off), and becomes red and itchy, with occasional blistering and/or weeping. The reaction may start a few minutes to a few hours after the victim leaves the water.
Treatment consists of a vigorous soap-and-water scrub, followed by a rinse with isopropyl (rubbing) alcohol. Apply 1 percent hydrocortisone lotion twice a day. If the reaction is severe, oral prednisone may be administered.
Also called "clamdigger's itch," swimmer's itch is caused by skin contact with cercariae, which are the immature larval forms of parasitic schistosomes (flatworms) found throughout the world in both fresh and salt waters. Snails and birds are the intermediate hosts for the flatworms. They release hundreds of fork-tailed microscopic cercariae into the water.
The affliction is contracted when a film of cercariae-infested water dries on exposed (uncovered by clothing) skin. The cercariae penetrate the outer layer of the skin, where itching is noted within minutes. Shortly afterwards, the skin becomes reddened and swollen, with an intense rash and, occasionally, hives. Blisters may develop over the next 24 to 48 hours.
Untreated, the affliction is limited to 1 to 2 weeks. Persons who have suffered swimmer's itch previously may be more severely affected on repeated exposures, which suggests that an allergic response may be a factor.
Swimmer's itch can be prevented by briskly rubbing the skin with a towel immediately after leaving the water, to prevent the cercariae from having time to penetrate the skin. Once the reaction has occurred, the skin should be lightly rinsed with isopropyl (rubbing) alcohol and then coated with calamine lotion. If the reaction is severe, the injured person may be treated with oral prednisone. Because the cercariae are present in greatest concentration in shallow, warmer water (where the snails are), swimmers should try to avoid these areas.
"Jellyfish" is the term commonly used to describe an enormous number of marine animals that are capable of inflicting a painful, and occasionally life-threatening, sting. These include fire coral, hydroids, jellyfishes (including "sea wasps") and anemones. The stings occur when the victim comes into contact with the creature's tentacles or other appendages, which may carry millions of small stinging cells, each equipped with venom and a microscopic stinger.
Depending on the species, size, geographic location, time of year and other natural factors, stings can range in severity from mild burning and skin redness to excruciating pain and severe blistering with generalized illness (nausea, vomiting, shortness of breath, muscle spasm and low blood pressure). Broken-off tentacles that are fragmented in the surf or washed up on the beach can retain their toxicity for months and should not be handled, even if they appear to be dried out and withered.
The dreaded box jellyfish (Chironex fleckeri) of northern Australia contains one of the most potent animal venoms known to man. A sting from one of these creatures can induce death in minutes from cessation of breathing, abnormal heart rhythms and profound low blood pressure (shock).
BE PREPARED TO TREAT AN ALLERGIC REACTION FOLLOWING A JELLYFISH STING. If possible, carry an allergy kit, including injectable epinephrine (adrenaline) and an oral antihistamine.
The following therapy is recommended for all unidentified jellyfish and other creatures with stinging cells:
For prevention of jellyfish sting or sea bather's eruption, all swimmers and ocean bathers are advised to apply Safe Sea jellyfish and sea lice safe sun block. This sunscreen product has been tested clinically and has been shown to help protect against the stings of most jellyfish and related creatures.
Paul Auerbach, M.D., M.S., is a consultant on hazardous marine life to DAN, medical editor for Dive Training magazine, advisor to numerous medical, recreational and scientific organizations and recognized internationally as a leading expert on the clinical management of hazardous marine encounters.
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