Refresher: When the dog bites (. . . when the cat nips)

Animal bites are a relatively common presenting problem at clinics and emergency departments across the country, especially when nicer weather brings humans and animals together more often outdoors.Even minor bite wounds are at high risk of infection and can involve other complications, such as tetanus or rabies. According to the Ottawa Handbook on Emergency Medicine—Bite Club: Comprehensive Guide to Bite Management, bite related injuries represent 1% of ED visits each year, with the most common bites being from dogs (90%) and cats (10%).“Bites can happen at any time but there is an uptick in summer,” said Dr. Michael Herman, an emergency physician in Ottawa and spokesperson for Canadian Association of Emergency Physicians. While farm animal and wild animal bites are more common in rural areas, dog and cat bites are “far and away” the most common ones in both urban and rural settings, he confirms. Other much less common bites are human, raccoon, squirrel and bats.Dog bitesCommon areas for bites are hands, feet and face, and they can be cosmetically deforming. If it’s deep into a joint or a tendon, said Dr. Herman, the bite can sometimes lead to impaired function. “Fortunately, most of the ones that we see are only skin deep.”The cornerstone of treatment for dog bites is immediate meticulous wound care, said Dr. Herman, referring to the CMAJ article Dog bites.“Everyone thinks about how dirty a dog or a cat's mouth is. When we’re assessing, the most important thing is immediate wound care for these injuries—cleaning it out with some kind of antiseptic solution, irrigating it very, very thoroughly with even just tap water to clear out any impregnated infection.”Dr. Herman said clinicians shouldn’t necessarily suture bites, “even if they're gaping. Closing over an area can make it more prone to infection. With bites on the hand, we very seldom close them over because they have such a high risk of infection when you do so. We would suture in an area that is cosmetically important, like a big gash across their face. If it's a very functional area, then it’s a bit of a discussion.”Cat bitesTreatment for cat bites is similar to that of their canine counterparts, but with a few other considerations.Infection is more common in cat bites for two reasons, said Dr. Herman. First, with teeth that are sharper and narrower than a dog’s, cat bites often puncture more deeply. Even though the wound doesn't look that bad on the surface, it is actually extending deeper into the skin and soft tissues and can more easily become infected. Secondly, “Dog bites tend to be more dramatic and people tend to present earlier. A patient has a big, gaping cut from a German Shepherd on their thigh, they’re going to see somebody about that. If they get a little nip from a cat, a little puncture on their arm, they clean it off and leave it,” he said.“Many cat bites I see are people coming in two, three days later and they're saying, ‘My cat gave me a little nip, I went about my day, and now I've got a big, red swollen arm.’”These two factors make cat bites stronger candidates for prophylactic antibiotics.When to use prophylaxisGenerally, antibiotic prophylaxis should be used for high-risk bite wounds, according to Bite Club: Comprehensive Guide to Bite Management. They should also be considered for immunocompromised patients or those on immunosuppressive agents. All patients who present with a bite (even from another human) should be asked if they have had a tetanus shot in the last 10 years and if not, get one promptly, said Dr. Herman.When to send patients to the EDDr. Herman said sometimes a well-meaning family physician has sent a patient to the ED thinking a bite needed stitches, only for the ED to evaluate and send the patient home.He said a trip to the ED would be warranted for serious bites that do need sutures or if there are signs of local or systemic infection. “Otherwise a physician in a clinic could reasonably do it themselves—the cleaning, dressing the wound, prescribing antibiotics. If there’s any concerns, they can always call into the ER and see what we think, and maybe save the patient a long unnecessary wait if I likely we wouldn't stitch it up.”When to consider rabiesWith any bite, rabies is a concern, especially if the biting animal is unknown. But while dogs and cats are required to get rabies shots in Canada, there hasn't been a human case of rabies since 1967.According to the Government of Canada Public Health Rabies site, since 2000, the number of reported rabies-positive animals has declined, largely due to control programs. In recent years, rabies infections have primarily been reported in:Bats: Canada-wideSkunks: Saskatchewan, Manitoba and OntarioRaccoons: Ontario, Quebec and New BrunswickFoxes: Nunavut, Northwest Territories, and northern parts of: Quebec, Manitoba and LabradorSo far in 2024, there have been a mere 18 bats, three skunks, two arctic foxes and one dog reported to have rabies.Health professionals should be aware of the rabies epidemiology in their region to help inform risk assessments for their patients, said Dr. Herman.“Most guidelines would say that if a patient has an encounter either with a bat that has bitten them or if they can't rule out that they've been bitten (for example, if they wake up with a bat in the room) the recommendation would be for rabies prophylaxis." On the other hand, cases with other animals are extremely rare in Canada. "For instance, Public Health Ontario guidelines would say that a squirrel that bites your hand would not be considered a high-risk encounter and wouldn't require rabies prophylaxis."For terrestrial animals, notes the CMAJ article Dog bites, if the biting animal presents any abnormal behaviour, such as hypersalivation, seizures, paralysis and irritability, rabies immunoglobulins and vaccine should be administered to the patient. See: Canada Public Health: Rabies for Health Professionals for further guidelines.

Refresher: When the dog bites (. . . when the cat nips)

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