What is Sea Urchin Toxicity?
Sea urchins, along with starfish, belong to a group of animals known as Echinodermata. Sea urchins are recognized by their round bodies covered with hardened, pointy spines. Some of these spines are rounded at the tip, while others are hollow and can inject venom. Sea urchins can also have tiny pincer-like structures, called pedicellariae, which can hold onto and inject venom, often with more venom than the spines.
These creatures possess a specialized tissue called stereom, unique to Echinoderms. It’s composed of a mineral called calcite, organized into a network-like structure, in addition to skin cells and fibers. The stereom forms part of the sea urchin’s internal skeleton and can develop into spines that get embedded into human tissue upon contact.
When people accidentally step on a sea urchin, its spines can cause painful puncture wounds, which result in immediate pain, bleeding, and swelling. They can also lead to severe muscle soreness, which can last up to a full day.
What Causes Sea Urchin Toxicity?
A sea urchin sting happens when one of its spines pierces the soft tissue of the skin. Sometimes the spine can snap off and stay lodged in the person. Retained spines can lead to tenosynovitis (swelling and irritation of the protective layer surrounding the tendons) or a granuloma (a small area of inflammation due to tissue injury).
Sea urchin stings can also cause symptoms affecting the whole body, such as feeling sick and throwing up, strange sensations like tingling or numbness, weakness, tummy pain, fainting, low blood pressure, and difficulty breathing.
Risk Factors and Frequency for Sea Urchin Toxicity
Although there isn’t a lot of information available, poisoning from sea urchins isn’t considered a big public health issue. There are many species of sea urchins in oceans all over the world. People like swimmers, fishermen, divers, and surfers can get poisoned by sea urchins, particularly in tropical and subtropical waters and areas near rocky shores. Based on reports from the American Association of Poison Control Centers, about 1800 aquatic exposures happen in the U.S. each year, with around 500 needing treatment.
Signs and Symptoms of Sea Urchin Toxicity
If someone accidentally steps on a sea urchin spine, they can expect to experience intense burning pain focused on the puncture wound, usually within the first 24 hours. Applying pressure to the wound often makes the pain worse. Along with the localized pain, other signs can include nausea, vomiting, tingling sensations, weakness, belly pain, fainting, low blood pressure, and difficulty in breathing. When the wounded area is inspected, bleeding, swelling, redness, and warmth can be observed. Sometimes, a sea urchin spine may be visible inside the wound. Sea urchin spines can leave dark blue or black marks on the skin around the wound that can resemble temporary tattoos.
- Severe localized burning pain
- Increased pain with pressure on the wound
- Nausea
- Vomiting
- Tingling sensations
- Weakness
- Abdominal pain
- Fainting
- Low blood pressure
- Difficulty breathing
- Bleeding, swelling, redness, and warmth at the wound site
- Presence of a sea urchin spine in the wound (not always visible)
- Dark blue or black “temporary tattoo” around the injury (particularly from dark-colored spines)
After the initial burning pain, other symptoms can develop such as swelling, redness, warmth, and bleeding in the area around the wound. In more severe cases, the person may experience nausea, vomiting, tingling sensations, muscle paralysis, and difficulty breathing. If a sea urchin spine penetrates a joint, it can lead to inflammation of the joint. Over time, there may be a secondary wound infection, or a small lump known as a granuloma might form in response to any lingering foreign matter.
Testing for Sea Urchin Toxicity
If you’ve been stung by a sea creature like a starfish or sea urchin (known as echinoderms), there are no specific lab tests to manage this type of venomous sting.
However, your doctor may use different types of imaging techniques to locate and remove any of this creature’s spines that might have been left in your body. These techniques could include X-rays, ultrasound (which uses sound waves to create images), computed tomography (CT scan which is a type of specialized X-ray), or magnetic resonance imaging (MRI which uses magnetic fields and radio waves to create detailed images).
Treatment Options for Sea Urchin Toxicity
When someone is injured by a sea urchin, the first thing we need to do is remove any visible spines quickly. These spines can keep releasing venom even after they’re detached from the urchin, worsening the damage. After removing the spines, we’ll usually place the wounded area in hot water, at a temperature you can comfortably tolerate. The warmth helps to alleviate the pain caused by the venom. We will also provide pain relief medicine to make you more comfortable.
It’s important to update your Tetanus vaccine as a precaution because injuries like these could potentially lead to Tetanus. If the pain persists, we might need to use local anesthetic to help numb the area. Using a nerve block, a technique where we temporarily numb a part of your body, might also help with the pain. The wounds will then need to be cleaned thoroughly to reduce the risk of infection. If there are any remaining spines that are easily visible and accessible, they will be removed.
If you notice a dark discoloration in the area where you were pricked, it could simply be dye that was released from the urchin. This should clear up within 48 hours. But if the spines have penetrated a joint or are very close to vital nerves and blood vessels, additional treatment like a splint or even surgery may be needed.
Some people may experience a nervous system reaction, known as reactive neuropathy, which could respond well to steroids. One thing to watch out for is infection, which can often occur after these types of injuries. Some people may notice small lumps, known as granulomas, forming around any remaining spines, which might need to be removed. You could also possibly get arthritis in the affected joint, which might need medical intervention.
Unfortunately, there isn’t any antidote available for sea urchin venom right now. The treatment mainly focuses on managing the symptoms and preventing complications. We typically wouldn’t give preventative antibiotics unless the wounds are deep, or if someone has underlying health conditions or a weakened immune system. If an infection does develop, the antibiotics prescribed will need to cover possible marine pathogens, including certain types of bacteria like Staphylococcus, Streptococcus, Vibrio vulnificus, and Mycobacterium marinum. Depending on the severity of the infection, you may need oral or intravenous antibiotics for a week to two weeks.
What else can Sea Urchin Toxicity be?
If you’re stung by an Echinoderm (a type of sea creature), it can potentially cause a few different health issues. However, these conditions can often be identified by the initial sting event and the symptoms that follow:
- Cellulitis: This is an inflammation of the skin and soft tissue. It can appear similar to the result of an Echinoderm sting. However, if you recall stepping on a spine and feeling immediate pain, this would suggest it’s not simple cellulitis.
- Contact Dermatitis: This skin condition can develop a few days after the stinging event and may appear like an ongoing infection. If you remember stepping on a spine while in the ocean, this should lead doctors away from diagnosing it as contact dermatitis.
- Anaphylaxis: Echinoderm stings can cause system-wide symptoms that can seem like anaphylaxis, a severe allergic reaction. If a patient is unstable and not able to provide a clear history during the initial presentation, doctors will provide supportive treatment.
It’s also important to note that the sting could come from specific types of Echinoderms like stingrays or starfish, which would require differentiated medical care.
What to expect with Sea Urchin Toxicity
Exposure to the venom of an echinoderm, a kind of sea animal, can cause effects that are local (affecting the area where you were stung) or systemic (affecting your whole body). However, it’s important to note that there’s no established connection between this venom and death, as per the information currently available in medical literature.
Possible Complications When Diagnosed with Sea Urchin Toxicity
The most frequent problems include symptoms that affect the whole body, such as the sudden failure of the heart and blood vessels to work properly (cardiovascular collapse) and skin infection (cellulitis).
Common Complications:
- Sudden heart and blood vessel failure (cardiovascular collapse)
- Skin infection (cellulitis)
Recovery from Sea Urchin Toxicity
If you need a surgical cleaning procedure (debridement), rest assured that your healthcare team will adhere to the common and well-established healthcare procedures to take care of you.
Preventing Sea Urchin Toxicity
It’s important for patients to be aware and cautious of their environment, especially when swimming or walking in large bodies of water. This is because most injuries from sea urchins occur when people accidentally step on their spines. Going barefoot, especially at night, should be avoided. Wearing shoes and diving gear can offer some protection, but keep in mind that these can still be pierced by a sharp sea urchin spine.
