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Sea Urchin Spine Punctures

I was chasing a big marble ray underwater near Cocos Island - I wanted to photograph it - and wasn't paying attention to my buoyancy. I brushed by a rock wall and suddenly felt severe burning in my arm and elbow. There were 15 black sea urchin spines sticking out of my forearm. The spines had gone right through my diveskin. I remembered hearing that it helps to urinate on a sea urchin sting, so I tried it, but it didn't help. Most of the black spots on my arm have disappeared, but I still can see two, and my wrist is starting to swell. What should I do?

Some sea urchins are covered with sharp venom-filled spines that can easily penetrate and break off into the skin. Others (found in the South Pacific) may have small pincerlike appendages that grasp their victims and inoculate them with venom from a sac within each pincer.
Sea urchin punctures or stings are painful wounds, most often of the hands or feet. If a person receives many wounds simultaneously, the reaction may be so severe as to cause extreme muscle spasm, difficulty in breathing, weakness and collapse.

The Treatment

  1. Immerse the wound in non-scalding hot water to tolerance (110 to 113 F / 43.3 to 45 C). This frequently provides pain relief. Other field remedies, such as application of vinegar or urine, are less likely to diminish the pain. If necessary, administer pain medication appropriate to control the pain.

  2. Carefully remove any readily visible spines. Do not dig around in the skin to try to fish them out - this risks crushing the spines and making them more difficult to remove. Do not intentionally crush the spines. Purple or black markings in the skin immediately after a sea urchin encounter do not necessarily indicate the presence of a retained spine fragment. The discoloration more likely is dye leached from the surface of a spine, commonly from a black urchin (Diadema species). The dye will be absorbed over 24 to 48 hours, and the discoloration will disappear. If there are still black markings after 48 to 72 hours, then a spine fragment is likely present.

  3. If the sting is caused by a species with pincer organs, use hot water immersion, then apply shaving cream or a soap paste and shave the area.

  4. Seek the care of a physician if spines are retained in the hand or foot, or near a joint. They may need to be removed surgically, to minimize infection, inflammation and damage to nerves or important blood vessels.

  5. If the wound shows any sign of infection (extreme redness, pus, swollen regional lymph glands) or if a spine has penetrated deeply into a joint, the injured person (particularly one with impairment of his or her immune system) should be started by a qualified health professional on an antibiotic, taking into consideration the possibility of a Vibrio infection (see #4 under "Coral Scrapes).

  6. If a spine puncture in the palm of the hand results in a persistent swollen finger(s) without any sign of infection (fever, redness, swollen lymph glands in the elbow or armpit), then it may become necessary to treat the injured person with a seven- to 14-day course of a non-steroidal anti-inflammatory drug (e.g., ibuprofen) or, in a more severe case, oral prednisone, a corticosteroid medication.

For more information on marine life injuries, see the complete article by Paul S. Auerbach, M.D., M.S. on Marine Life Trauma from the Jan/Feb 1998 issue of Alert Diver.