Scuba Diving: Fire Coral Cuts

Medical Author:

Fire Coral Facts

  • Fire corals are not true corals. Fire corals (Millepora alcicornis) are members of the Cnidaria phylum, and although fire coral looks like coral, it is a member of the class Hydrozoa and more closely related to jellyfish and other stinging anemones.
  • Fire corals are typically encountered off the Florida coast, in the Caribbean reefs and across the Bermuda platform.
  • In addition, fire corals are sessile (fixed in one place) creatures that can attach to rocks, coral, seaweed, or pilings.
  • The painful stings of M. alcicornis are inflicted using the cnidae (stinging threads), which are released from a cnidoblast on its surface. These are used to stun prey.
  • Fire coral have minimal toxicity.
  • These organisms inflict predominantly local pain, usually described as stinging or burning, and possible rash.
  • Fire corals have a bright yellow-green and brown skeletal covering and are widely distributed in tropical and subtropical waters.
  • Scuba divers often mistake fire coral for seaweed, and accidental contact is common.
  • The very small cnidoblast (an organ in some marine animals consisting of a minute capsule) on fire corals contain tentacles that protrude from numerous surface pores. In addition, fire corals have a sharp, calcified external skeleton that can scrape the skin.

What Are the Symptoms of Fire Coral Cuts and Stings?

  • Within 5-30 minutes following skin contact with fire coral, an immediate burning sensation or a stinging pain develops.
  • A red rash with raised wheals or vesicles appears, and itching develops.
  • Lymph gland swelling may occur over time.
  • Rarely, nausea and vomiting have been reported.
  • Fire coral cuts are treated like all other coral cuts.

What Is the Treatment of Fire Coral Cuts and Stings?

The following guidelines are suggested to treat fire coral cuts:

  • Rinse with seawater. Avoid fresh water because it will increase pain.
  • Apply topical acetic acid (vinegar) or isopropyl alcohol. This treatment can inactivate the venom (toxin).
  • Remove any parts of the fire coral with tweezers or with tape after treating with acetic acid or isopropyl alcohol; this will help remove the toxin that causes the symptoms.
  • Immobilize the extremity because movement may cause the venom (toxin) to spread.
  • Apply hydrocortisone cream two to three times daily as needed for itching. Discontinue immediately if any signs of infection appear.

If the person who has come into contact with fire coral develops shortness of breath; swelling of the tongue, face, or throat; or other signs of an allergic reaction, the patient should be treated for an allergic reaction. If no signs of allergic reaction are present, pain may be relieved with one to two tablets of acetaminophen (Tylenol) every 4 hours (not to exceed 3 grams in a 24 hour time period) and/or one to two tablets of ibuprofen (Motrin, Advil) every 6-8 hours. Some health care professionals prefer naproxen (Aleve) for pain treatment.

When Should I Call the Doctor about Fire Coral Cuts and Stings?

  • In severe cases, seek medical treatment as soon as possible.
  • Consult a doctor for treatment with available medications, especially if the affected area develops pus, or a blister more than 3/16 of an inch (5mm) in diameter (bullae) forms with any read streaks that appear on the skin. If itching lasts more than a few days or pus or blister (bullae) develops with topical hydrocortisone treatment, seek medical care immediately.

Pictures of Fire Coral and Fire Coral Stings

Picture of Fire Coral, Image Courtesy of Cecil Berry
Picture of Fire Coral, Image Courtesy of Cecil Berry Click to view larger image.

Picture of Fire Coral Sting on Torso
Picture of Fire Coral Sting on Torso Click to view larger image.

Reviewed on 11/21/2017

Medically reviewed John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care

REFERENCE:

MedscapeReference.com. Cnidaria Envenomation.

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