Jellyfish and Stingray Stings

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Box Jellyfish Sting Marks

Summer is the season when coastal dwellers head to the deep blue sea (well, the shallow parts of it, at least) and enjoy a cool dip in the water. Some unlucky bathers might, however, run afoul of sea creatures that can cause painful injuries. You’re probably thinking of sharks.


Although sharks get all the publicity (and will be discussed in a future article), Jellyfish cause 150 million injuries a year throughout the world. Jellies are marine animals with a fascinating life cycle that would remind you of an alien life form. Many spend part of their life on the seabed, then become free-swimming in their reproductive (often called “medusa”) stage.

Jellyfish don’t bite, but have tentacles with millions of stinging cells called “nematocysts” that injure millions of swimmers every year by injecting them with a type of venom. Species to watch out for include the Portuguese man of war, the box jellyfish, the sea nettle, and others.

“Medusa” stage

The symptoms may present as very minor to, rarely, life-threatening. They include:

• Local throbbing, burning pain with irritation.
• Muscle spasms.
• Itching.
• Swelling.
• Reddish-brown or purple tracks corresponding to where tentacles contacted the skin.
• Nausea and vomiting.
• Weakness.
• Confusion.

Some note the development of blisters and other reactions up to one or two weeks after a sting. In severe envenomation, shortness of breath, rapid pulse, and other heart and lung symptoms may manifest, dependent on the dose of venom injected into the body. It should be noted that the tentacles of dead jellyfish on the shore may still impart venom if stepped on or touched.

Remove any visible stingers with tweezers or even a credit card, but avoid rubbing the area. Once removed, skin irritations may be treated with oral antihistamines like diphenhydramine (Benadryl) or calamine lotion, as well as topical steroids like hydrocortisone one percent cream or ointment. Ibuprofen or acetaminophen may be required for pain. If the injury is near the eye, thorough flushing is advised.

Burning sensations may be relieved with a rinse using sea (not fresh) water; Heating the sea water is thought to be more effective in soothing the pain. Different sources advocate vinegar, witch hazel, urine, rubbing alcohol, baking soda paste, and other substances as treatment. These may inactivate the nematocysts, but vary in their effectiveness or could worsen the condition, dependent on the individual victim and the species of jellyfish involved. The medic should determine the right treatment for jellies in their area before a disaster occurs. Expect symptoms to last from a few days to a few weeks.

To prevent jellyfish stings, avoid swimming on the occasions when they swarm (also called a bloom). This is often seasonal. It may be wise to avoid the shore altogether during these times. If you must enter the water, do so with protective clothing. Wear shoes if walking on the beach.


Blue Spotted Stingray (Alex Borland/public domain)

Another creature responsible for more injuries than sharks is a relative: the stingray. Stingrays are flat, roundish, and seem to fly in the water with fins that look like wings. They’re most often seen in warmer climates. Like Jellyfish, stingrays don’t bite but defend themselves with stingers.

A stingray’s tail contains one or more barbed spines, each containing venom which can be very painful when injected into an unwary victim. This usually occurs by accidentally stepping on it, so expect most injuries to be in the feet, ankle, or lower legs. Wounds appear as punctures or small lacerations. The venom can be lethal, however, if injected into the chest or abdomen, as occurred with the famous wildlife expert Steve Irwin.

The list of symptoms the victim experiences is extensive. It includes:

• Bleeding.
• Extreme pain.
• Swelling.
• Dizziness.
• Anxiety.
• Sweating.
• Nausea and Vomiting.
• Muscle cramps.
• Skin discoloration.

In the worst cases, the victim may complain of irregular heartbeats, shortness of breath, muscle paralysis, fainting, and even seizures. Treating a sting would involve:

• Stopping the bleeding with pressure.
• Flushing the wound and removing barbs and debris (tweezers will help).
• Soaking in hot (not scalding) water. Heat can inactivate the venom.
• Scrubbing the wound with soap and fresh water.
• Avoiding wound closure unless absolutely necessary.

Remove any visible barbs from the wound, but avoid rubbing the area. Once removed, skin irritations may be treated with oral antihistamines like diphenhydramine (Benadryl) or calamine lotion, as well as topical steroids like hydrocortisone one percent cream or ointment. Ibuprofen or acetaminophen may be required for pain.

Lionfish (public domain/Jacky Weyenbergh

Antibiotics like doxycycline 100 mg orally twice a day for 7 days may be helpful to prevent infection. It should be noted that treatment strategies for stingrays can work on injuries caused by venomous spined catfish, scorpion fish, and certain other toxic sea creatures.

Joe Alton MD

Joe Alton MD aka Dr. Bones

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