Plantar sea urchin spine injury after travel to Thailand: clinical, dermoscopic and optical coherence tomography documentation with practical recommendations

Abstract

Sea urchin spine injuries are frequent marine related puncture injuries in tropical and subtropical travel settings. Retained fragments may cause persistent pain, foreign body granuloma, tenosynovitis, synovitis, arthritis or infection. We report a 38 year old woman who stepped on a sea urchin on the penultimate day of a vacation in Thailand. She presented after travel with multiple punctate brown black lesions on the plantar hallux and forefoot. She was afebrile, C reactive protein was below the detection limit and tetanus protection had been refreshed before travel during pre travel medical counseling. Clinical examination and dermoscopy demonstrated superficial foreign body associated puncture lesions. Visible and accessible fragments were removed, and macroscopic inspection showed dark, longitudinally ridged, tapering fragments consistent with sea urchin spine material. Dermoscopy guided optical coherence tomography (OCT) was performed as adjunctive documentation and showed focal superficial architectural disruption, hyperreflective signal alteration and posterior attenuation at selected puncture sites. OCT did not determine treatment. Topical antiseptic wound care was performed and the clinical course was uncomplicated. This case highlights a structured approach to plantar sea urchin injuries: careful removal of visible accessible fragments, wound cleansing, pain control, tetanus assessment, patient education and selective conventional imaging or referral when deeper retention or critical structure involvement is suspected.