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Seabather's Eruption

Topic Overview

What is seabather's eruption?

Seabather's eruption is a rash that occurs when a swimmer is stung by marine life larvae. The condition has many names, including sea lice, pika-pika, sea poisoning, sea critters, and ocean itch.

What causes seabather's eruption?

Two types of marine life that generally cause this rash are:

  • Thimble jellyfish (Linuche unguiculata). These are found seasonally in the water off the Florida coast and across the Caribbean. The jellyfish breed in the Caribbean throughout the summer, peaking in May. The larvae are barely visible, appearing like a speck of finely ground pepper.
  • Sea anemone (Edwardsiella lineata). These are found in the water off the coast of Long Island, New York. The larvae are small (2 mm to 3 mm).

Other types of marine life may also cause this rash.

What are the symptoms of seabather's eruption?

Shortly after being stung, a swimmer may complain of skin discomfort. The rash develops in a few minutes to 12 hours after swimming. The rash consists of raised, hard or soft bumps, or blisters of different shapes and sizes that appear very red and may be extremely itchy. The larvae can become trapped in the fabric of a swimsuit, under swim caps and fins, and along the cuff edges of wet suits and T-shirts. The rash often appears in areas of the body that were covered.

Occasionally, other symptoms may occur with the rash, including nausea, vomiting, headache, fatigue, a general feeling of illness (malaise), pinkeye (conjunctivitis), and urethritis, the inflammation of the tube that carries urine from the bladder to outside of the body (urethra). Fever may occur, particularly in children.

Can seabather's eruption be treated at home?

Home treatment can help ease your discomfort and prevent other problems.

  • Do not rub your skin. If larvae are on your skin, rubbing will cause them to sting.
  • Remove your swimsuit as soon as possible. Since larvae can become trapped in the fabric of your suit, it is important to remove a contaminated suit to prevent more stings. If available, rinse your suit in household vinegar or rubbing alcohol. Wash your suit in hot, soapy water and dry it in a dryer, if possible, before you wear it again.
  • Shower with fresh water. Apply soap and vigorously scrub your skin. Do not shower with a contaminated suit on. If larvae are trapped in the fabric of a suit, a freshwater shower will cause the larvae to sting.
  • Take an antihistamine, such as diphenhydramine or chlorpheniramine, or apply hydrocortisone cream (1%) to help control itching. Note: Do not use the cream on children younger than age 2 unless your doctor tells you to. Do not use in the rectal or vaginal area in children younger than age 12 unless your doctor tells you to. Also, don't give antihistamines to your child unless you've checked with the doctor first.
  • Use an ice pack to help relieve pain.
  • Keep the rash clean. Wash it every day with soap and water.

Does seabather's eruption require medical treatment?

The rash will usually go away without medical treatment in 10 to 14 days. Watch for symptoms of infection while the rash is present. These include:

  • Increased pain, swelling, redness, or warmth around the affected area.
  • Red streaks extending from the affected area.
  • Drainage of pus from the area.
  • Fever or chills with no other known cause.

If these symptoms are present, seek medical attention.

Credits

By Healthwise Staff
William H. Blahd, Jr., MD, FACEP - Emergency Medicine
David Messenger, MD
Last Revised April 22, 2013

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