Dermatology Online Journal

Shark skin laceration
Sean D Doherty, Ted Rosen MD
Dermatology Online Journal 12 (6): 6

Department of Dermatology, Baylor College of Medicine, Houston, Texas

---

Abstract

We present a case of multiple lacerations occurring from an encounter with a bull shark in which violent contact was made with the animal's rough skin. Conservative treatment of the injury resulted in good clinical outcome without any complications. Such events are only rarely reported in the medical literature.

---

Introduction

Despite humankind's fear of sharks, only about 50 to 100 shark attacks occur every year worldwide, with about 10-15 deaths ensuing. More individuals die each year of lightening strikes than of shark bites! The most aggressive sharks include the bull shark, the tiger shark, and the great white shark [1]. Sharks have been reported to inflict wounds on man by means other than biting. One of these includes "bumping," in which the shark makes a close pass by the victim. This action may result in lacerations and abrasions from the shark's rough skin [2, 3]. There are relatively few reports in the medical literature describing the clinical management and outcome of shark-bite injuries [4]. Injuries resulting from shark bumping are even more rarely described and chronicled.

Clinical synopsis

A 50-year-old man presented after being struck with the tail of a bull shark. While the patient was spear fishing in the Bahamas and bringing a bloody fish back to the boat, he saw the animal approach. The shark brushed against his arm and then hit the patient's left leg with its tail in a backward swinging motion, causing immediate, searing pain. The patient managed to climb aboard his boat, tie a tourniquet around a deeply lacerated leg, and captain his ship back to port. Following emergency triage, a compression dressing was applied, and he was given both an antibiotic shot (unknown type) and a tetanus booster.

At presentation, one week following the accident, the patient had a superficial abrasion on his left forearm and a deep linear laceration on his left, lateral foreleg. The depth of the laceration was to the level of the subcutis, but there was no exposed muscle or fascia. There was some nonviable tissue present and swelling around the area (Fig. 1). There was no widespread surrounding erythema, tenderness or purulent exudate.

Figure 1	Figure 2
Figure 1: One week after shark encounter Figure 2: Five weeks after injury

Figure 3	Figure 4
Figure 3: Eight weeks after injury Figure 4: Healed laceration at 12 weeks

All black-colored, seemingly nonviable tissue was debrided. The patient was instructed to perform a saline rinse three times per day, followed by liberal application of mupirocin ointment. The wound was wrapped with a light compression bandage. The patient was initially given acetaminophen 500 mg / hydrocodone 5 mg for analgesia as needed. Over the next several months, the wound healed well (Figs. 2, 3). The patient had no residual debility and only a moderate linear scar remained at 3 months (Fig. 4).

Discussion

Shark skin is covered with overlapping, spiny scales that are termed dermal denticles because of their structural similarity to teeth. These denticles have a plate-like base supporting a main body composed of dentine with an enameloid capping and a central pulp cavity. The denticles function to protect the shark and to reduce frictional drag [5]. The apex of the denticles points toward the tail which is why a shark feels relatively smooth when stroked from head to tail, but rough with a sandpaper texture when stroked in the opposite direction.

Unprovoked shark attacks may take different forms. A shark can bite a victim without warning, or it can "bump" the victim prior to attacking. It is thought that the bumping may be an attempt to assess the potential danger of potential prey or even be employed to injure or partially incapacitate prey. Bumps may also occur from sharks without any subsequent bite. When performed at speed, these bumps may result in serious abrasions or long, deep lacerations in the skin and underlying tissue, as was experienced by this patient [6].

Many shark bites and shark-inflicted wounds become infected. The ocean contains an array of atypical bacteria capable of infecting humans. The best described of these are Vibrio spp. and Aeromonas spp. [6, 7]. These bacteria may be associated with rapidly progressive infections that can appear within hours of exposure. If a physician encounters a shark attack victim acutely, empiric antibiotic therapy should be started to cover the above-referenced organisms, as well as Streptococcal and Staphylococcal species. A broad spectrum cephalosporin would be a reasonable choice in this instance. Tetanus prophylaxis should be given upon arrival to a medical care facility [6]. Additional systemic antibiotic therapy was not initiated in this patient because he was not seen until one week following the attack, he had already received some parenteral antibacterial treatment, and there were no overt signs of infection at the time of presentation.

In patients who present non-acutely with abrasions and lacerations from shark bumping and have no signs of infection, conservative therapy appears to be appropriate. All apparent nonviable tissue should be removed, and saline rinses, mupirocin ointment, and compression wraps should assist in achieving optimal healing without any sequelae. To facilitate healing, the patient should be cautioned against vigorous use of the affected limb and encouraged to avoid such activities as contact sports.

Conclusion

We present a rare case of a shark-induced injury resulting from bumping. This activity can occur with or without an associated shark bite. If encountered acutely, these injuries should be empirically treated with antibiotics. Conservative treatment of the injury consisting of debridement of nonviable tissue, frequent saline rinses, mupirocin ointment, and compression wraps led to a good clinical outcome in this case, without any complications.

References

1. Burnett JW. Aquatic adversaries: shark bites. Cutis. 1998 Jun;61(6):317-8. PubMed

2. Baldridge HD, Williams J. Shark attack: feeding or fighting? Milit Med. 1969 Feb;134(2):130-3. PubMed

3. Byard RW, Gilbert JD, Brown K. Pathologic features of fatal shark attacks. Am J Forensic Med Pathol. 2000 Sep;21(3):225-9. PubMed

4. Woolgar JD, Cliff G, Nair R, Hafez H, Robbs JV. Shark attack: review of 86 consecutive cases. J Trauma. 2001 May;50(5):887-91. PubMed

5. Southall EJ, Sims DW. Shark skin: a function in feeding. Proc Biol Sci. 2003 Aug;270 Suppl 1:S47-9. PubMed

6. Caldicott DG, Mahajani R, Kuhn M. The anatomy of a shark attack: a case report and review of the literature. Injury. 2001 Jul;32(6):445-53. PubMed

7. Pavia AT, Bryan JA, Maher KL, Hester TR Jr, Farmer JJ III. Vibrio carchariae infection after a shark bite. Ann Intern Med. 1989 Jul;111(1):85-6. PubMed

© 2006 Dermatology Online Journal