Stepped on a sea urchin in Thailand? What to do (and coral cuts too)

Are sea urchins in Thailand dangerous?

Sea urchins are common on rocks and coral in shallow water all around Thailand, including the bays of Koh Phi Phi. The ones visitors most often meet are black with long, thin spines. They don’t attack. You get stung by stepping on one, putting your hand on a rock, or brushing past while snorkelling at low tide.

The spines are brittle and break off in the skin. Some species also carry a mild venom. A sting causes sharp, burning pain, and the skin around it may swell and look dark from the dye in the spines. For most people it is painful but not dangerous. The bigger risks come later: spines left deep in the skin, spines in a joint, and infection, which is more likely in warm tropical water.

Sea urchin sting: what to do

This first aid follows the NHS advice for sea creature stings:

• Get local help if you can: a lifeguard, boat crew, dive centre or someone with first aid training.
• Rinse the area with seawater, not fresh water.
• Remove spines that stick out of the skin with tweezers, pulling gently in the direction they went in. Don’t squeeze, which can snap them.
• Soak the area in hot water, as hot as you can tolerate without scalding, for at least 30 minutes. Test the water with an unaffected hand first, especially for children. Hot towels work if you can’t soak it.
• Ask a pharmacist about pain relief, and tell them about any medication or allergies.

What not to do: don’t pee on the wound, don’t put ice on it, don’t touch spines with bare hands, and don’t close or tightly cover the wound. Don’t try to dig out spines that have broken off under the skin with a needle or knife: this pushes them deeper and raises the risk of infection.

Sea urchin spines in your foot: will they come out?

Small spine fragments that are only just under the skin often work their way out over days or weeks, or are broken down by the body. You may see dark dots under the skin. These are often dye from the spines rather than the spines themselves, and fade within a few days.

Spines that are deep, in the sole of the foot where you put weight on them, or near a joint such as a toe or knuckle are different. They can cause ongoing pain, swelling, stiffness and infection, and a doctor may need to remove them. A clinic can check the wound and tell you whether you need an X-ray or treatment on the mainland.

Coral cuts: why they need extra care

Scrapes and cuts from coral are just as common as urchin stings, and they are easy to underestimate. Coral is sharp, the cuts are often dirty, and wounds that stay wet in warm seawater are slow to heal and prone to infection. Look after them properly from the start:

• Rinse the cut thoroughly with clean bottled water to wash out sand and coral fragments.
• Clean it gently with soap and water, then dry it and apply an antiseptic. A pharmacist can recommend one.
• Cover it with a clean, dry dressing and change it every day, or when it gets wet.
• Stay out of the sea until the cut has started to heal, or keep it covered with a waterproof dressing.
• Check it every day for signs of infection.

Sea urchin FAQ

Sea urchin stings: your questions