2011-07-14 / Healthy Living

When the jellyfish stings, and the sealice larvae bite

BY DR. SHAUNA KRANENDONK, M.D.
Special to Florida Weekly


Jellyfish washed up on Daytona Beach. Jellyfish washed up on Daytona Beach. Summer in Florida means time at the beach. Reading, swimming in the ocean and exercising are great reasons to hit the beach. Getting a little color to compliment a new summer outfit is not. But tanning and skin cancer aside, there are several skin-related mishaps that can make your day at the beach anything but a day at the beach.

Scenario 1: After a refreshing dip in the ocean, upon leaving the water you develop a strange, prickling sensation under your bathing suit. This is followed in a few hours by the onset of itchy, red welts under the areas covered by your bathing suit, which typically resolves within a few days.

Diagnosis: Seabather’s Eruption aka sealice. The cause is exposure to the larvae of the thimble jellyfish. The larvae are most prevalent in Florida waters between March and August, peaking in late May. When swimming, they can become trapped beneath the swimsuit. Upon leaving the water, the nematocysts (harpoon-like organelle on the jellyfish larvae) fire into the skin, causing the stinging sensation.

If you experience symptoms, remove your swimsuit and towel off your skin. If diluted vinegar is available, apply it to your skin prior to showering to neutralize any additional toxin. If a rash occurs, mild cases can be treated with over-the counter oral antihistamines (Benadryl) and hydrocortisone 1% cream applied 2-3 times a day. More severe cases may require a trip to your dermatologist’s office for prescription strength corticosteroids creams.

Swimsuits should be thoroughly washed in fresh water and detergent and dried prior to reuse to prevent recurrence. Avoidance is possible only by staying out of the ocean when “sealice” warnings are posted. Wearing smaller swimsuits can help by reducing the surface area of larvae to be trapped, but if you choose that option, just be sure to cover up the extra exposed skin with a good sunblock.

Scenario 2: While swimming, you feel a sharp, stinging sensation on your arm.

Diagnosis: Jellyfish sting. What to do? Get out of the water immediately, as some jellyfish stings can cause a sudden drop in blood pressure, nausea, vomiting and shock. Once on shore, apply vinegar to the site to neutralize the jellyfish toxin (Palm Beach Ocean Rescue lifeguards keep vinegar at their stations). Do not rinse with fresh water as this will cause more stinging. Do not try to remove the tentacles with your hands. Instead, scrape off the tentacles with the edge of a credit card or drivers license. If symptoms such as lightheadedness, nausea or vomiting occur, proceed at once to the nearest emergency room.

Scenario 3: You’re enjoying a barefoot stroll along the beach when you feel a sharp pain on the bottom of your foot.

Diagnosis: Laceration (cut) due to a broken shell. Treatment: Hold pressure on the wound until any bleeding has stopped. Next, wash the area with soap and fresh water to remove any sand, dirt or remaining debris. Do not rinse the wound in salt water as it could increase the risk of infection. Use a clean tweezers to remove any visible foreign object. If the laceration is deep, seek medical attention at the nearest emergency room as stitches may be required. Otherwise, apply diluted betadine to the site, followed by a layer of antibiotic ointment such as bacitracin and cover with a bandage. If the wound is a deep puncture, be sure you’ve had a tetanus shot (to prevent lockjaw) within the last 10 years. Most US citizens have received a series of 3 vaccines as a child. If the object which punctured is particularly dirty, a tetanus booster may be needed if it has been more than 5 years since the last tetanus shot.

Scenario 4: You forget to reapply your broad-spectrum sunblock (SPF 30 or higher) and two hours later, you feel a hot, tender sensation on your chest.

Diagnosis: Sunburn. Treatment: Get out of the sun immediately. Effects from sunburn generally peak 12-24 hours later. Severe cases with widespread blistering, severe pain, headache, confusion, or flu-like symptoms should be treated in an emergency room. Mild cases can be treated at home. A pain reliever, such as ibuprofen, naproxen or aspirin should be started early to reduce both pain and inflammation. Cool compresses with equal parts milk and water, or Burow’s solution (available in drug stores) applied with a soft clean cloth, can be applied for 15 minutes every 2-4 hours. This can be followed by application of hydrocortisone 1% cream and/or aloe based gels (also available in drug stores). ¦

Return to top