Dermatology Made Easy is based on the most popular topics from DermNet NZ's vast array of material. The book combines the essential focus of the ‘Made Easy’ book series with the authority and knowledge base of DermNet NZ's unparalleled resources.
Author: Jenna Beaumont. Final year medical student, University of Auckland. Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, May 2015.
The majority of animal bites received by humans are dog bites (85–90%), followed by cat bites (5–10%) and rodent bites (2–3%).
Human bites constitute 2–3% of animal bites received by humans.
Most dog bites in young children occur on the head and neck. In older children and adults, they are more commonly situated on the arms and legs. This is likely due to the level of these body parts in relation to the mouths of large dogs.
Dog bites commonly result in crush injuries, but may also cause scratches, deep cuts, puncture wounds, and tearing of the skin and underlying flesh.
Most cat bites occur on the arms and the hands. Cat bites typically result in either scratches or deep puncture wounds.
Complications of animal bites include:
Wound infection can lead to:
Up to 20% of dog bite wounds become infected. Most dog bite wound infections are polymicrobial. The most common pathogens are:
Cat bite wounds are more likely to become infected than dog bite wounds, due to the tendency of cat bites to result in deep puncture wounds. Bites located on the hands have a greater risk of leading to further complications such as osteomyelitis or septic arthritis. The most common pathogens are:
Bartonella henselae, the causative agent of catscratch disease , can also be transmitted via a bite from an infected cat.
Approximately 20% of rodent bite wounds become infected. The most common pathogens are:
Bites from rodents infected with Streptobacillus moniliformis or Spirillum minus can result in rat bite fever, a rare systemic illness that can be serious or fatal if untreated. Patients with rat bite fever typically present 10 days to 4 weeks after a rodent bite with fever, rash, and septic arthritis.
Although New Zealand is free of rabies, the risk of an animal bite being infected with rabies must be considered if the bite occurred outside of New Zealand.
An animal bite wound should be carefully examined and treated as soon as possible after it has occurred to reduce the risk of complications.
If you have been bitten by an animal, consult a doctor:
Antibiotic prophylaxis should be considered for high risk wounds, such as:
Amoxicillin clavulanate is the first-line antibiotic for animal wounds. Other options are:
Indications for hospital referral include:
A tetanus booster (tetanus toxoid) should be offered to patients if it has been more than 5 years since their last dose and they have completed their primary vaccination course. If they have not previously been fully immunised against tetanus, they should be offered tetanus toxoid plus tetanus immunoglobulin.
Rabies post-exposure prophylaxis should be considered for all bites that occurred overseas in a rabies endemic area.
See the DermNet NZ bookstore.
© 2018 DermNet New Zealand Trust.
DermNet NZ does not provide an online consultation service. If you have any concerns with your skin or its treatment, see a dermatologist for advice.