Coral cuts are lacerations or abrasions sustained from contact with coral (phylum Cnidaria) during marine activities. These wounds are notoriously slow to heal due to a combination of retained foreign material (calcium carbonate fragments), nematocyst envenomation (especially from fire coral), and inoculation with marine pathogens including halophilic gram-negative bacteria and nontuberculous mycobacteria. [1-4]
1. History
- Mechanism: direct skin contact with coral while swimming, snorkeling, diving, or wading — typically hands, shins, feet, knees
- Timing: when did the injury occur, and was there immediate pain/stinging (suggests fire coral or other cnidarian component)?
- Water type: saltwater, brackish, or reef environment; geographic location (tropical vs. temperate)
- Contamination: was the wound exposed to sand, sediment, or organic debris?
- Symptom progression: initial stinging → persistent pain → delayed healing, erythema, purulent drainage
- Prior wound care: was the wound irrigated? Was vinegar or hot water applied? Any self-treatment with antibiotics?
- Important negatives: fever, lymphangitis, joint involvement, systemic symptoms
2. Alarm Features
- Rapidly spreading cellulitis or necrotizing fasciitis — suggests Vibrio vulnificus or other virulent marine pathogen [5-6]
- Hemorrhagic bullae, ecthyma gangrenosum, or crepitus
- Fever, rigors, or sepsis signs
- Lymphangitic streaking or sporotrichoid spread (consider Mycobacterium marinum) [7-8]
- Joint involvement or tenosynovitis near the wound
- Wound deterioration despite standard antibiotics (consider atypical mycobacteria or retained foreign body) [9]
- Immunocompromised host or chronic liver disease — dramatically increased risk of fulminant Vibrio infection [1][5]
3. Medications
- Minor wounds in immunocompetent hosts: prophylactic antibiotics generally not required [1][10]
- Immunocompromised or liver disease: prophylactic oral ciprofloxacin or TMP-SMX recommended [1]
- Infected wounds (empiric): must cover marine gram-negative organisms — doxycycline + ceftazidime, or a fluoroquinolone (ciprofloxacin or levofloxacin) [2][5][11]
- Penicillin, ampicillin, erythromycin, and first-generation cephalosporins are NOT acceptable for marine wound infections — most marine bacteria are resistant [1][6][12]
- Late-onset granulomatous infection (M. marinum): clarithromycin + ethambutol (or rifampin) for 3–6 months [8][13-14]
- Topical: wound cleansing with tap water or saline; topical antibiotic ointment for minor abrasions [15-16]
- Pain: NSAIDs or acetaminophen; consider topical lidocaine for fire coral stings
- Tetanus prophylaxis must be current in all cases [1][17]
4. Diet
- No specific dietary restrictions for coral cuts
- Adequate hydration and protein intake support wound healing
- Patients with chronic liver disease (especially with elevated serum iron) are at markedly increased risk for Vibrio infection — counsel on avoidance of raw shellfish and marine wound exposure [1]
5. Review of Systems
- Constitutional: fever, chills, malaise (systemic infection)
- Skin: spreading erythema, new nodules, drainage, delayed healing
- MSK: joint pain or swelling near wound (septic arthritis, tenosynovitis)
- Lymphatic: lymphadenopathy, lymphangitic streaking
- GI/Hepatic: history of liver disease (Vibrio risk factor)
- Immune: HIV status, immunosuppressive medications, diabetes
6. Collateral History and Family History
- Travel history: geographic location of coral exposure (Caribbean, Indo-Pacific, Red Sea)
- Occupation: fisherman, dive instructor, marine biologist (recurrent exposure)
- Aquarium exposure at home (M. marinum risk) [8][14]
- Immunosuppressive medications or chronic illness
- Family history generally not contributory unless hereditary immunodeficiency
7. Risk Factors
- Immunosuppression (HIV, transplant, biologics) — risk of disseminated Vibrio or mycobacterial infection [1][5]
- Chronic liver disease (especially cirrhosis with elevated iron) — Vibrio vulnificus septicemia can be fatal [1]
- Diabetes mellitus — impaired wound healing and infection risk
- Deep puncture wounds, large lacerations, wounds near joints [1]
- Delayed presentation or inadequate initial wound care [12]
- Contamination with sediment or organic matter [1]
- Peripheral vascular disease
8. Differential Diagnosis
- Coral cut with secondary bacterial infection (Vibrio spp., Staphylococcus, Streptococcus, Pseudomonas) — most common [1-2][18]
- Fire coral contact dermatitis — immediate urticarial reaction, vesicles, lichenoid plaques over weeks [19]
- Mycobacterium marinum ("fish tank granuloma") — indolent papulonodular or sporotrichoid lesions appearing weeks after exposure [7-8]
- Mycobacterium haemophilum — chronic granulomata, difficult to culture [9]
- Erysipelothrix rhusiopathiae (erysipeloid) — well-demarcated violaceous plaque [1-2]
- Sea urchin spine granuloma — if concurrent sea urchin contact
- Retained foreign body reaction — persistent inflammation from embedded coral fragments [20]
- Cellulitis from terrestrial pathogens — if wound secondarily contaminated on land
- Necrotizing fasciitis — cannot-miss diagnosis with rapidly progressive infection [5]
9. Past Medical History
- Prior coral injuries or marine wound infections
- Hepatic disease (cirrhosis, hepatitis) — critical for Vibrio risk stratification
- Diabetes, peripheral vascular disease
- Immunosuppressive conditions or medications
- Tetanus immunization status
- Allergies to antibiotics (fluoroquinolones, doxycycline)
10. Physical Exam
- Vital signs: fever, tachycardia (systemic infection)
- Wound inspection: laceration vs. abrasion; depth; visible foreign material (white calcium carbonate fragments); necrotic tissue
- Surrounding skin: erythema, warmth, induration, lymphangitic streaking, bullae, crepitus
- Palpation: tenderness, fluctuance (abscess), subcutaneous emphysema
- Distal neurovascular exam: especially for hand/foot wounds
- Joint assessment: range of motion, effusion if wound near a joint
- Lymph nodes: regional lymphadenopathy
- Sporotrichoid pattern: linear nodules tracking proximally along lymphatics (M. marinum) [7-8]
11. Lab Studies
- Minor clean wounds: no labs needed
- Signs of infection:
- CBC with differential
- CRP, ESR (if chronic/indolent infection suspected)
- Blood cultures (if febrile or septic)
- Wound culture — alert the lab to use sodium chloride–supplemented media and thiosulfate-citrate-bile-sucrose (TCBS) agar for Vibrio detection [1]
- BMP, LFTs (if systemic illness or liver disease suspected)
- Chronic non-healing wound: AFB culture at 30°C (M. marinum grows optimally at 30–33°C, not 37°C), tissue biopsy for histopathology and PCR [8][21]
12. Imaging
- Plain radiographs: first-line if retained foreign body suspected (coral fragments are radiopaque calcium carbonate) [2][20]
- Ultrasound: useful for localizing small or radiolucent foreign bodies [20]
- MRI: if deep tissue infection, tenosynovitis, or osteomyelitis suspected
- CT: rarely needed; consider for complex hand/foot injuries with concern for joint involvement
- Imaging unnecessary for superficial abrasions without foreign body concern
13. Special Tests
- Wound culture on specialized media (TCBS agar, NaCl-supplemented media) [1]
- AFB culture at 30°C for M. marinum if chronic granulomatous lesion [8]
- Tissue biopsy: granulomatous inflammation on histology supports mycobacterial infection [21]
- PCR for mycobacterial species identification [8]
- Wood's lamp: not typically useful
- Point-of-care ultrasound: foreign body detection
14. ECG
- Generally not indicated for coral cuts
- Consider if box jellyfish or Irukandji envenomation is concurrent (cardiac arrhythmias, QT prolongation) [3]
- ECG indicated if patient develops sepsis with hemodynamic instability
15. Assessment
Coral cuts produce a unique wound combining mechanical laceration, potential cnidarian envenomation, and marine bacterial inoculation. The calcium carbonate skeleton of coral causes ragged wounds with embedded fragments that act as foreign bodies, promoting chronic inflammation and delayed healing. Fire coral (Millepora spp.) adds a nematocyst-mediated contact dermatitis component. [3][19]
Severity stratification:
- Mild: superficial abrasion, no foreign body, no signs of infection
- Moderate: deeper laceration, retained fragments, early cellulitis
- Severe: rapidly spreading infection, systemic toxicity, deep structure involvement, immunocompromised host
Atypical presentations include indolent granulomatous nodules appearing weeks to months later (M. marinum), which are frequently misdiagnosed and treated with ineffective standard antibiotics. [7-9]
16. Treatment Plan
Initial wound care
- Copious irrigation with tap water or normal saline under pressure [15-16]
- Careful removal of all visible coral fragments (debridement under magnification if needed) [2]
- Do NOT close coral wounds primarily — leave open or use delayed primary closure due to high contamination risk
- Moist wound environment with occlusive dressing [15-16]
- Tetanus prophylaxis if not current [1][17]
Fire coral component
- Rinse with seawater (NOT fresh water, which can trigger nematocyst discharge) [3]
- Apply vinegar (5% acetic acid) to inactivate nematocysts in tropical species [3]
- Hot water immersion (45°C for 20 minutes) for pain from heat-labile venom [2-3]
- Topical corticosteroids and oral antihistamines for contact dermatitis [19]
Antibiotic therapy
- Minor wounds, immunocompetent: no prophylactic antibiotics [1]
- Immunocompromised/liver disease: oral ciprofloxacin or TMP-SMX prophylactically [1]
- Established infection: doxycycline + ceftazidime (saltwater), or fluoroquinolone monotherapy [2][11]
- Parenteral options for severe infection: ceftazidime, cefotaxime, gentamicin, or tobramycin [1]
- Fulminant infection: consider imipenem-cilastatin [1]
- M. marinum: clarithromycin + ethambutol for 3–6 months [8][13-14]
The following algorithm from Auerbach (NEJM) summarizes the approach to marine envenomation management:
17. Disposition
- Discharge: most minor coral cuts — superficial abrasions/lacerations in immunocompetent patients with adequate wound care
- Observation/short stay: moderate wounds requiring debridement, wounds with retained foreign bodies
- Admission criteria:
- Rapidly progressive cellulitis or necrotizing fasciitis
- Sepsis or systemic toxicity
- Deep structure involvement (joint, tendon, bone)
- Immunocompromised patient with significant wound
- Need for IV antibiotics or operative debridement
- Specialist consultation: hand surgery (hand/wrist wounds with deep involvement), infectious disease (atypical or refractory infections), dermatology (chronic granulomatous lesions)
18. Follow Up / Return Precautions
- Follow-up: wound check in 48–72 hours for any wound with infection risk; sooner if signs of worsening
- Return immediately for:
- Increasing redness, swelling, warmth, or pain
- Red streaking up the limb
- Fever or chills
- Purulent drainage or foul odor
- New blisters or skin discoloration
- Patient counseling:
- Coral cuts heal slowly (weeks to months) — this is expected
- Keep wound clean and moist; avoid submersion in natural water bodies until healed
- Complete any prescribed antibiotic course
- If nodules or bumps develop weeks later along the limb, return for evaluation (M. marinum) [7-8]
- Expected course: superficial wounds typically heal in 2–6 weeks with proper care; deeper wounds or those with retained fragments may take longer
References
1. Marine Envenomations. — Auerbach PS. The New England Journal of Medicine. 1991.
2. Management of Extremity Trauma and Related Infections Occurring in the Aquatic Environment. — Noonburg GE. The Journal of the American Academy of Orthopaedic Surgeons. 2005.
3. Poisonings, Envenomations, and Toxic Exposures During Travel. — Arthur Chang and Michael Yeh CDC Yellow Book. 2025.
4. Marine Bacteria Complicating Seawater Near-Drowning and Marine Wounds: A Hypothesis. — Sims JK, Enomoto PI, Frankel RI, Wong LM. Annals of Emergency Medicine. 1983.
5. Post-Travel Dermatologic Conditions. — Karolyn A. Wanat and Scott A. Norton CDC Yellow Book. 2025.
6. Skin, Soft Tissue and Systemic Bacterial Infections Following Aquatic Injuries and Exposures. — Diaz JH, Lopez FA. The American Journal of the Medical Sciences. 2015.
7. Under the Sea: Superficial Skin Infection With an Atypical Cause. — Hansen CE, Ascher DP, Kim HS, Schwartz RH. Pediatric Emergency Care. 2017.
8. Mycobacterium Marinum: A Brief Update for Clinical Purposes. — Canetti D, Riccardi N, Antonello RM, Nozza S, Sotgiu G. European Journal of Internal Medicine. 2022.
9. Chronic Cutaneous Mycobacterium Haemophilum Infection Acquired From Coral Injury. — Smith S, Taylor GD, Fanning EA. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2003.
10. Evaluation and Management of Traumatic Lacerations. — Singer AJ, Hollander JE, Quinn JV. The New England Journal of Medicine. 1997.
11. Antibiotic Prophylaxis in Injury: An American Association for the Surgery of Trauma Critical Care Committee Clinical Consensus Document. — Appelbaum RD, Farrell MS, Gelbard RB, et al. Trauma Surgery & Acute Care Open. 2023.
12. Analysis of Clinical Characteristics, Pathogen Infection, and Drug Sensitivity of Marine Injury Patients: A Cross-Sectional Study. — Ge L, Gao Y, Wang K, et al. Medicine. 2022.
13. Current Treatment Options for Cutaneous Infections. — Medel-Plaza M, Esteban J. Expert Opinion on Pharmacotherapy. 2023.
14. Fish Tank Exposure and Cutaneous Infections Due to Mycobacterium Marinum: Tuberculin Skin Testing, Treatment, and Prevention. — Lewis FM, Marsh BJ, von Reyn CF. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2003.
15. 2024 American Heart Association and American Red Cross Guidelines for First Aid. — Hewett Brumberg EK, Douma MJ, Alibertis K, et al. Circulation. 2024.
16. Current Management of Acute Cutaneous Wounds. — Singer AJ, Dagum AB. The New England Journal of Medicine. 2008.
17. Common Questions About Wound Care. — Worster B, Zawora MQ, Hsieh C. American Family Physician. 2015.
18. Vibrio Alginolyticus Cellulitis Following Coral Injury. — Patterson TF, Bell SR, Bia FJ. The Yale Journal of Biology and Medicine. 1988.
19. Red Sea Coral Contact Dermatitis. — Addy JH. International Journal of Dermatology. 1991.
20. Management of Foreign Bodies in the Skin. — Halaas GW. American Family Physician. 2007.
21. Diagnosis and Therapy of Mycobacterium Marinum: A Single-Center 21-Year Retrospective Analysis. — Strobel K, Sickenberger C, Schoen C, et al. Journal Der Deutschen Dermatologischen Gesellschaft = Journal of the German Society of Dermatology : JDDG. 2022.