Sea urchin sting: first aid and when to get help

Sea urchins live on rocks, reefs and shallow sea floors, and on Puerto Rico's beaches it is easy to step on or brush against one while wading. According to the Merck Manual, the spines cause a painful puncture wound, break off easily in the skin and, if they stay in, can cause lasting pain and inflammation. Joint and muscle pain and a rash can also follow.

A small bluish or purple dot where a spine went in helps show where it is. If you were stung by a jellyfish or a Portuguese man o' war instead, see jellyfish stings in Puerto Rico.

According to the Merck Manual, a spine that went in deep or has moved deeper may need surgical removal, and it can lodge against a bone or a nerve. When it can't be seen, an X-ray helps find it. Pain that lasts beyond 5 to 7 days should raise the question of infection or a piece of spine left inside.

So if a spine is near a joint (a finger, ankle or knee), if you have many deep spines, or if you have trouble moving the injured part, you need an in-person evaluation. The doctor tells you so on video and, if needed, refers you for an X-ray or for removal.

You see Dr. Diana Nieves Castro, a Puerto Rico-licensed general practice physician with several years of emergency-department experience, in English or Spanish. On video the doctor looks at the wound, asks where and when it happened, how much it hurts and whether you can move the injured part, and checks for signs of infection.

She tells you what to do at home, when to go in person, and whether you are due a tetanus booster (the Merck Manual recommends one for these wounds; the shot is given in person). If appropriate, the doctor prescribes and we send your prescription to your pharmacy, for example if the wound has become infected. We do not prescribe controlled substances. If you see pus or spreading redness, read about skin infection (cellulitis).

On vacation? See our care for tourists and visitors. You need to be physically in Puerto Rico during the visit. We see adults and children of all ages; if the patient is under 21, a parent or legal guardian stays on camera for the whole visit and shows photo ID.

Request a visit online 24/7 — we confirm your time by email or text. Book a visit, choose "Doctor visit" and pay by card. We send you a secure video link. It works on your phone, tablet or computer.

A doctor visit costs US$79, the same price for every age, with no membership. You get a full refund if the visit can't take place. We do not bill insurance; on request we give you an itemized receipt (superbill). See prices.

Call 911 for trouble breathing, swelling of the face or throat, or fainting after the sting. Go to an ER or urgent care center the same day if a spine is inside a joint, you can't move the injured part, or you have a fever with spreading redness. See when to go to the ER.

Wear water shoes on rocks, reefs and grassy sea floors, watch where you step, and don't handle sea urchins. With children, check their feet and hands when they come out of the water.