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What to Know About Sea Urchin Stings

Medically Reviewed by Dan Brennan, MD on June 10, 2021

Sea urchins are sphere-shaped or flat creatures that live in the ocean and are completely covered in protective spines. On the tips of these spines are tiny claw-like pincers called pedicellariae.

Sea urchins won’t attack you, but because they live in shallow water and like to hide near rocks, you could step on or touch one accidentally. 

You probably won’t get stung if you lightly touch a sea urchin, but if you make contact with any amount of pressure, like if you step on a sea urchin, the sea urchin’s pedicellariae will likely release venom and sting you.

Sea urchin stings aren’t usually fatal, but they are dangerous. You should be aware of the symptoms and treatments so you can get professional help if you need it.

Symptoms

If you get stung, your symptoms could vary depending on which of the 950 species of sea urchin has stung you. The most common symptoms for a single, shallow-water sea urchin puncture include:

  • Swelling in and around the area where you were stung
  • Redness around the spine’s entrance point
  • Sensitivity or pain
  • Infection if the sting is not treated
  • Blue coloring where the spine pierced your skin
  • Muscle aches

If a sea urchin stings you more than once when you encounter it, your symptoms will be more serious and may likely include:

Treatment

There are several ways you can treat a sea urchin sting at home. Try following these steps to cure your symptoms:

  • Soak the affected area in hot water for at least an hour.
  • If the sea urchin’s spine broke off and is stuck in your skin, pluck it out with tweezers.
  • If there are pedicellariae in your skin, cover the area with shaving cream and lightly scrape with a razor.
  • Flush and scrub the sting with soap and water.
  • Leave the injury open. Do not bandage it.
  • Take regular doses of acetaminophen or ibuprofen to relieve pain.

Another possible method for removing the spine involves using vinegar because it helps dissolve spines. Soak the affected area in vinegar or place a vinegar-soaked cloth on it. Alternate between vinegar and hot water a few times a day.

The most important thing you can do is take the spine and pedicellariae out as soon as possible. If you can’t get the spine out yourself, you’ll need to visit your healthcare provider. They will make a small incision or perform surgery to remove it, depending on how deep into your skin the spine has traveled.

If you’re feeling any of the more serious side effects or if you were stung near your elbow, knee, or other joint, seek emergency help immediately.

Complications

If your injury is extreme or if you don’t treat it correctly, you can face serious health consequences. Paralysis, respiratory failure, tissue necrosis, and death are all possible complications of sea urchin stings.

Tissue necrosis is when skin cells don’t get enough oxygen or blood, and they die. It happens after the skin undergoes an external injury or serious trauma. If you have tissue necrosis, the affected part of your skin will be painful, red, swollen, numb, and have blisters. You can avoid it by keeping your sea urchin sting clean.

If you leave a spine or pedicellariae in your skin for too long, it will burrow deeper into your skin. If it gets too deep into your tissue, it could cause dermatitis, joint and muscle pain, or a granulomatous nodular lesion.

A granulomatous nodular lesion is a clump of cells that form small nodules, or bumps, underneath the skin. They happen when something irritating pierces the skin. Your body forms granulomatous nodular lesions to try and keep strange substances, like sea urchin venom, from spreading.

To avoid all of these complications, contact a healthcare provider as soon as you notice any serious symptoms or if you have symptoms for more than a week.

Prevention

If you’re in shallow or rocky areas of the ocean, keep an eye out for sea urchins. Watch where you step and where you put your hands to avoid surprise contact with them. Don’t go into the ocean at night if you know there are sea urchins in the area.

Wearing water shoes or flippers might protect you from stepping on a sea urchin’s spines. A sharp spine or a high-pressure touch will still probably end up in a sting, even if you are wearing something on your feet.

For the health of sea urchins, you shouldn’t touch them. If you have to touch one to move it out of your way, for example, handle it carefully and avoid putting too much pressure on the spines.

If you’re unsure how serious your urchin sting is, contact your healthcare provider for a diagnosis and more information on how to treat your injury.

WebMD Medical Reference

Sources

SOURCES:

eMedicineHealth: “Sea Urchin Stings and Puncture Wounds.”

Healthdirect: “Granulomas.”

Medanta: “Necrotic Tissue.”

MedicineNet: “Can Sea Urchins Kill You?”

Merck Manual: “Sea Urchin Stings.”

StatPearls: “Sea Urchin Toxicity.”

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