Sea Urchin Toxicity

Sea urchins are part of the phylum Echinodermata which also includes starfish. Sea urchins have globular bodies covered by calcified spines. The spines are either rounded at the tip or hollow for envenomation. The also can have pedicellariae that can grasp and envenomate, typically with more venom than in the spines. Echinoderms possess a distinctive endoskeletal tissue called stereom, which is composed of calcite organized into a mesh-like structure, in addition to dermal cells and fibers. Stereom forms structural elements that can embed into human tissue as spines. When stepped on, these spines cause painful puncture wounds with immediate pain, bleeding, and edema. They can cause severe muscle ache which can last up to 24 hours.