Sea Anemone Image

Soaking in hot water for 60-90 minutes (see below) is said to offer relief from the pain and swelling (Paul Cianci). Others espouse magnesium sulfate pastes (Carl Edmonds). Snake bite suction cups are used by some to remove the spines while others go ahead and excise the area conservatively under local anesthesia.

Surgery is indicated for a foreign body reaction and intra-articular puncture, the latter being probably the most serious consequence of the accident.

Topical antibiotics and tetanus protection should be offered.

The following is from the Merck Manual:
"Echinoderms: Pedicellariae stings are treated by washing the area and applying an antihistamine-analgesic-corticosteroid balm. Sea urchin spines should be removed immediately. A bluish discoloration at the site of entry may help in locating the spine, which may sometimes be seen by xeroradiogram. Vinegar dissolves most superficial spines, and soaking the wound in vinegar several times/day and covering the area with a wet vinegar compress may be sufficient; surgery is seldom necessary at this point. If a small incision needs to be made to extract the spine, care must be taken as it is very fragile. In time, a spine may migrate into deeper tissues and require surgical removal.

Bill Chambers, Scuba Instructor, has the following advice re treatment of sea urchin spines: "These days, I simply place (usually a foot) the injured part into hot (comfortably hot) vinegar (black or white) that has been warmed in a microwave oven. In less than ten minutes, the pain is gone and the spines themselves look like half dissolved granules of sand in the bottom of the container.The wound heals as if nothing more than a minor splinter had been the problem."

Sam Shelanski, MD of  Rodales Scuba Diving advises:
Rx:
If possible, elevate the affected area and apply a pressure bandage. Both techniques will help slow the absorption of any venom in the wound. Do not apply a tourniquet. This will generally result in more damage than it will prevent.

Immerse the wound in 45C/115F water, or as hot as you can tolerate, for 30 to 90 minutes. Many marine toxins are proteins which are destroyed by heat, much like what happens to an egg when it's hard-boiled. A hot soak can dramatically reduce the pain, and amount of damage, caused by a sting.

Control the pain. The pain from marine stings can be excruciating and lead to shock, making pain control an important early step in wound care. This can generally be done with local anesthetics, and very rarely will require the use of systemic pain relievers or narcotics.

Cleanse the wound with an antiseptic solution. Washing out remaining venom and pieces of spine will help minimize damage, speed healing and prevent infection. Leave an inaccessible spine alone only if it hasn't penetrated a joint, nerve or blood vessel.

Seek appropriate medical care. Despite doing all of the above, some wounds will require surgical cleansing and repair, antibiotics for infection control, as well as antivenins and life support for severe stings. It is not always immediately obvious which stings will need more intensive medical care, so if at all possible, get care for all stings.

Reference

Hand injuries from sea urchin spines
MB Strauss and RI MacDonald write in the journal Clin Orthop 1976 Jan-Feb;(114):216-8

"Sea urchin spine injury is usually a benign process that rarely comes to the attention of a physician. Aside from the transient episode of excruciating pain which responds dramatically to hot water soaks, there is usually no residual disability. As in any puncture wound, tetanus prophylaxis and observation for latent infection is advised. Complications arise, however, when spines are embedded over bony prominences, within joints, or in contact with nerves. Cases are associated with sea urchin injuries has not been previously reported in the literature. When such injuries necessitate exploration, aseptic surgical technique is required. "