Introduction
Background
Animal bites are common, with more than 4.7 million people (almost 2% of the population) in the United States affected each year, according to the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia. Typically, these are dog or cat bites, with the patient's age most commonly being 7-9 years, but persons of any age can be affected. Typically, the aggressor is a dog, such as a collie, a boxer, or a German shepherd. Other animal bites include bites caused by small animals, such as rabbits, ferrets, monkeys, and farm animals.
Certain breeds of animals tend to be more dangerous, and, based on a recent study by the CDC, Allstate Insurance Company comprised a list of 8 dogs they won't insure against bites. On the list are Akitas, boxers, chow chows, Doberman pinschers, pit bulls, American Staffordshire bull terriers, rottweilers, and wolf hybrids.1
In the United States, snakes account for 8000 bites per year. These snakes are typically pit viper types, including rattlesnakes, copperheads, cottonmouth water moccasins, and coral snakes. Many of these snake bites occur after hurricanes and floods (eg, Hurricane Katrina) and may be avoided or mitigated with sensible precautions.2
Interestingly, a recent retrospective study by Bhattacharjee et al3 showed that animal bites increase significantly during a full moon. This study, performed in England, tabulated animal bites in the emergency department (ED) on all days of the month, showing this surprising result.
Pathophysiology
The body site on which dog bites occur varies with age; however, the hand is most frequently involved in cat bites.
Snakebites can cause a variety of symptoms, including diarrhea, a burning sensation and pain at the wound site, convulsions, fainting, dizziness, weakness, blurred vision, fever, increased thirst, nausea and vomiting, numbness and tingling, and tachycardia.
Dog bites may cause infections by Staphylococcus, Streptococcus, Eikenella, Pasteurella, Proteus, Klebsiella, Haemophilus, Enterobacter, Capnocytophaga (formerly CDC group DF-2), and Bacteroides species. Cat bites may cause infections by Pasteurella, Actinomyces, Propionibacterium, Bacteroides, Fusobacterium, Clostridium, Wolinella, Peptostreptococcus, Staphylococcus, and Streptococcus species.
Frequency
United States
The incidence of dog bites is 4.7 million people per year in the United States, and the incidence of snake bites is 8000 cases per year. Data collected by the University of Pittsburgh show the median age of persons who sustain dog bites is 15 years, with a significant increase in boys aged 5-9 years.4 While the overall incidence for dog bites is 12.9 cases per 10,000 individuals, the incidence in boys aged 5-9 years is 60 cases per 10,000 individuals.4
Mortality/Morbidity
Annually, in the United States, 10-20 people receive bites that are fatal. Elderly people are more susceptible to animal bites because their ability to fend off attacks is compromised.
Although mortality is rare with most animal bites in the United States, morbidity is common, especially with cat bites infected by Pasteurella species. Dog bites may become infected by Pasteurella species as well.
From 1979 to 1996, 304 people in the United States died from dog bites, according to data from the CDC.
- In bites by rabid animals, morbidity can result in significant illness. Although bites by rabid dogs comprise 16% of cases, bites by rabid skunks, foxes, and bats comprise most cases. Squirrel bites and hamster bites rarely cause rabies.
- According to the Humane Society of the United States5 , from January 1997 to December 1998, 27 people died from dog bites, 19 of whom were children younger than 12 years and 8 of whom were adults (mostly elderly persons). Most bites are nonfatal, with 230,000 nonfatal bites for every fatal bite.
- Sepsis can occur in immunocompromised persons with infections caused by Capnocytophaga organisms.
Sex
Males are typically bitten by dogs; usually, young males are most frequently affected. Conversely, women are more frequently bitten by cats than are men.
Age
As a result of their vulnerability and increased possibility of exposure to the animals, individuals who are bitten are usually younger or older persons.
Clinical
History
Usually, patients with animal bites present to the ED. Occasionally, patients may present to the dermatology office. In either case, inquire about the following:
- Circumstances leading to the animal bite and disruption of skin integrity
- Immunization status of the aggressing animal and whether the patient has reason to believe that the animal has rabies
- Treatment administered up to the time of admission to the ED (Patients may have used folk remedies or performed treatments that may lead to other infections.)
- Immunization status for tetanus (Immunize patients if their immunizations are not up-to-date.)
Physical
- Observe the patient with an animal bite for disruption of the skin's integrity. Prescribe antibiotics if disruption of the skin is noted.
- In patients with snakebites, look for signs of toxicity, including pain, diarrhea, a burning sensation, seizures, syncope, dizziness, blurred vision, hyperhidrosis, fever, increased thirst, loss of coordination, nausea, vomiting, dysesthesias, and tachycardia.
- If the bite is deep, neurovascular events may have occurred, and injury to tendons and bones must be excluded.
- Foreign bodies may be observed in the wound.
Causes
Usually, causes of animal bites are related to the possibility of exposure to the animals.
- Most animal bites involve young children who may play with or inadvertently tease a dog or an animal that attacks the child.
- Less often, cat bites are associated with severe trauma, but they can result in infection with Pasteurella multocida, thereby causing a significant medical problem.
- Snakebites occur frequently in campers or hikers in wilderness areas.
More on Animal Bites |
 Overview: Animal Bites |
| Differential Diagnoses & Workup: Animal Bites |
| Treatment & Medication: Animal Bites |
| Follow-up: Animal Bites |
| References |
| Next Page » |
References
Leech M. Insuring Is Hard With Dog - Firms Won't Write Policies For Some Pooch Owners. Los Angeles Daily News. August 2, 2002.
North Carolina A&T State University, US Department of Agriculture. Dealing with Snakes After a Storm or Flood. Adapted by P. Bromley from Alabama Cooperative Extension Service. North Carolina State University. Available at http://www.ces.ncsu.edu/disaster/factsheets/pdf/snakes.pdf. Accessed 2002.
Bhattacharjee C, Bradley P, Smith M, Scally AJ, Wilson BJ. Do animals bite more during a full moon? Retrospective observational analysis. BMJ. Dec 23-30 2000;321(7276):1559-61. [Medline].
Weiss HB, Friedman DI, Coben JH. Incidence of dog bite injuries treated in emergency departments. JAMA. Jan 7 1998;279(1):51-3. [Medline].
The Humane Society of the United States. Preventing and Avoiding Dog Bites. 2001. Humane Society. Available at http://www.hsus.org. Accessed July 5, 2001.
Arndt KA, LeBoit PE, Robinson JK. Skin infections caused by unusual bacterial pathogens. In: Cutaneous Medicine and Surgery. Vol 2. Philadelphia, Pa: WB Saunders; 1996:939-48.
Bruce S, Schroeder TL, Ellner K, Rubin H, Williams T, Wolf JE Jr. Armadillo exposure and Hansen's disease: an epidemiologic survey in southern Texas. J Am Acad Dermatol. Aug 2000;43(2 Pt 1):223-8. [Medline].
Cunningham BB, Paller AS, Katz BZ. Rat bite fever in a pet lover. J Am Acad Dermatol. Feb 1998;38(2 Pt 2):330-2. [Medline].
Doud Galli SK, Miller JP. Animal Bites. eMedicine from WebMD [serial online]. August 1, 2006;Available at http://www.emedicine.com/ent/topic725.htm.
Epstein ME, Amodio-Groton M, Sadick NS. Antimicrobial agents for the dermatologist. II. Macrolides, fluoroquinolones, rifamycins, tetracyclines, trimethoprim-sulfamethoxazole, and clindamycin. J Am Acad Dermatol. Sep 1997;37(3 Pt 1):365-81; quiz 382-4. [Medline].
Fitzpatrick TB, Eisen AZ, Wolff K. Animal bites, infestations, and insect bites and stings. In: Baker AS, ed. Fitzpatricks Dermatology in General Medicine. Vol 1. New York, NY: McGraw-Hill; 1987:2468-76.
Mayo Foundation for Medical Education and Research. Bites and Stings. December 20, 2000. Mayo Clinic. Available at http://www.mayohealth.org. Accessed July 5, 2001.
Spanierman C. Animal Bites. eMedicine from WebMD [serial online]. March 30, 2006;Available at http://www.emedicine.com/ped/topic107.htm.
Stump J. Bites, Animal. eMedicine from WebMD [serial online]. Februrary 2, 2006;Available at http://www.emedicine.com/emerg/topic60.htm.
Further Reading
Keywords
dog bites, cat bites, rabies, snakebites, hand bites
