Sea urchin granuloma secondary to Strongylocentrotus purpuratus and Strongylocentrotus franciscanus

Sea urchin injuries have been associated with a variety of cutaneous lesions, ranging from acute, transient reactions, to more chronic inflammatory conditions that result in the formation of granulomas. Although diverse species of sea urchins have been reported to produce chronic cutaneous granulomas, the two most prevalent organisms found on the US West Coast, purple and red sea urchins (Strongylocentrotus purpuratus and Strongylocentrotus franciscanus), have not yet been reported to induce persistent granulomatosis in humans. We describe one case of a 35-year-old marine biologist with chronic cutaneous lesions produced after repeated exposures. The lesions were similar to the ones produced by other urchin species, consisting of small, firm, erythematous nodules on his palms, dorsum of the hands, elbows, and knees. Increased awareness of this condition, including its association with the two prevalent organisms on the West Coast, should lead to a more rapid diagnosis for those affected. This article reviews the types of injuries, clinical cutaneoous lesions, histopathological features, and pathogenesis of the chronic inflammatory process induced by sea urchins.