Levi is an 8-year-old Quarter Horse X gelding that developed and unusual wound along the cranial (forward) aspect of his neck just below the left jugular groove during the spring of 2015. Levi's owner was not aware of any injury to the area preceding the appearance of the wound.
The owner texted a photo of the wound to The Atlanta Equine Clinic, who scheduled an appointment for Levi's evaluation and treatment.
The Original Texted Photo
The black color evident at the center of the wound was very suggestive of tissue necrosis (death), which often occurs as a consequence of blood supply loss and/or exposure to toxin(s).
Closer examination was performed the following morning at the barn. Inflamed, swollen and red tissue surrounding a fairly large circular region of dead skin was evident.
The Appearance of the Wound During Initial Examination
The dead skin was surgically removed, exposing a large (empty) defect within the underlying tissue. The appearance of the wound was highly suggestive of local tissue necrosis secondary to copperhead snake venom infiltration.
The Appearance of the Wound After Initial Debridement
Tissue necrosis of this type generally occurs secondary to poisonous spider or snake bites. Necrosis occurs from infiltration of hemotoxins into the tissue and/or anaerobic bacterial infection occurring in association with the bite.
Levi was stabled in close proximity to a water body (pond), which was situated within about 100 yards of his pasture. Copperhead snakes tend to reside near water.
Spider and snake bites are often difficult to detect during the acute phase due to the small puncture size of the bite. Most manifest after tissue necrosis is already well underway, as was the case with Levi.
In the vast majority of cases, snake bites occur along the horse's muzzle, face and neck, since these structures are leading and close to the ground as the horse moves in a forward direction. Spider bites tend to be more randomly located on the horse.
Fortunately, Levi's bite did not violate a major blood vessel, as this could have resulted in a life-threatening condition. Like most venomous bites, the reaction (although painful) was confined to a relatively small region and therefore did not pose a serious threat to Levi's overall well-being.
It should be noted that excessive swelling around the horse's muzzle must be addressed quickly so as to avoid occlusion of the airway and subsequent asphyxiation.
In Levi's case, treatment consisted primarily of debriding necrotic tissue and treating secondary anaerobic infection of tissue. The majority of the latter is accomplished via "aerating" the wound during debridement; anaerobic bacteria cannot survive in the presence of oxygen.
Supplemental antibiotic therapy was implemented to accelerate healing. Topical Wound Ointment was applied to stimulate granulation and filling of the defect.
The defect filled within a couple days of initiating treatment.
Within 6 weeks only a small visible remnant of the injury remained.
Levi has since resumed his day-to-day activities at the farm.
If you suspect that your horse has been bitten by a poisonous snake or spider, contact your veterinarian immediately.