Marine Toxin Dermatitis

Your exam shows you have an injury to your skin from a marine toxin, venom, or parasite. Exposure in fresh water lakes may cause swimmer's itch which is due to parasites transmitted by birds and snails. In the ocean, this is called seabather's eruption. If your skin begins itching after a swim, shower as soon as possible and change into dry clothes. These parasite skin irritations require no specific treatment except medicine to control itching.

The following creatures can cause an irritating reaction in the skin: sea urchins, sponges, jellyfish, coral, anemones, and sting rays. Sea urchins cause harm when their spines penetrate human skin and break off to cause a wound. These spines can also penetrate rubber soled shoes and wet suits. Treatment is removal of the spines completely. Hot water may inactivate the toxin on the spines. Coral can cause mild toxic effects, however coral cuts that are not properly treated can produce infection in your skin. Use a lot of water to clean out the wound. All foreign matter (bits of coral in the skin) must be removed. A tetanus shot is usually needed. Wounds should be left open and signs of infection should be monitored (fever, swelling, redness, pain, pus). Sting ray injuries may be life threatening and immediate medical attention is needed. Most injuries from sting rays are encountered from unintentional stepping on the sting ray buried in shallow surf near the shore in the late summer and early fall. To avoid this, shuffle your feet along the bottom when walking.

The most important part of treating marine venoms is to make sure there is no foreign body or toxin left on the skin or under it. Jellyfish and Portuguese Man-o-War stings can be very painful and dangerous. First aid for these stings includes:

  • Spray the skin with vinegar, or spread a thin mixture of baking soda or meat tenderizer over the affected area of skin.

  • Sea water can be used to help wash off the toxic cysts. Use shaving cream and a razor to help remove the cysts. A plastic object (such as a credit card) can also be used.

  • Do not immerse affected extremity in cool fresh water.

  • Avoid vigorous rubbing of affected area.

  • Seabather's eruption is usually treated with topical antihistamines and corticosteroids.

Emergency medical care is needed for treatment of serious jellyfish sting reactions. Sometimes patients get repeated reactions in the same site, scarring and pigment changes. Be sure to see your doctor for follow-up to be certain you are getting the best treatment.


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.