Sea Urchins

Sea UrchinsVancou

Sea urchins are echinoderms-distantly related to starfishes and are covered with spines used for defense.

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 pincer like 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 as a swimmer or diver has unintentionally probed against an urchin

If a person receives many venomous wounds simultaneously a reaction may cause extreme muscle spasm, difficulty in breathing, weakness and collapse.

Immediate Treatment for bites includes

• Immerse the wound in non-scalding hot water to tolerance (43.3 to 45 C). This frequently provides pain relief. This is useful for other marine envemations as well and is useful if unsure what stung them
• If available, administer pain medication appropriate to control the pain.
• 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. Never intentionally crush the spines.

One week we saw 2 groups of travelers who had swam separately in the Mexican Pacific and Aegean Sea. In both groups of patients the stings only caused local inflammation and pain. Some of the spines were removed with application and peeling of rubber cement and even bikini waxing was used.

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.

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.

Seek the care of a physician if spines are retained in the hand or foot, or near a joint.

X-rays will help determine this. They may need to be removed surgically, to minimize infection, inflammation and damage to nerves or important blood vessels.

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 doctor on an antibiotic, taking into consideration the possibility of a marine infection which are aggressive.

If traveling in a foreign land activate the local emergency medical service to get first aid.

The Divers Alert Network is a free consulting service that may also direct travelers and scuba divers with medical emergencies (www.diversalertnetwork.com).