Dog Bite - Care and Treatment

The dog may even be the man's best friend, but that does not stop millions of people are bitten by these animals every year. There are no reliable data in Brazil, but in the US it is estimated about 4.5 million people bitten by dogs, with varying degrees of severity, every year. Children, especially those between 5 and 9 years are the most affected. Of these 4.5 million bites, about 900,000 (20%) evolve with wound infection.


When a person is bitten by a dog, the first thing that comes to mind is the risk of infection by rabies virus. Currently, however, anger is not the main complication of canine mordias, as this is a relatively rare disease nowadays. The most frequent complications of dog bites are bacterial infection caused injury or traumatic injury of the skin, muscles, vessels, nerves and tendons, especially when the bite is caused by large dogs and strong jaw muscles, such as Pitbull, Rottweiler, Mastiff, German Shepherd and Brazilian Fila.

In this article we will explain what are the most common problems that can arise as a result of a bite of dog and what are the treatments and care to minimize the risk of complications.

Types of dog bite

Depending on the dog breed, the bites can cause basically three types of injury: perforation, laceration or crush.

The last two types of bite are those that have the highest risk of serious injury to internal structures, including bone fracture, or leave permanent scars on the skin. Since the penetrating bites have the highest risk of complication of wound contamination and the development of bacterial skin infections.

Any dog bite can cause an infection, but penetrating wounds are the most dangerous because they inoculate natural bacteria dog's mouth deep into the skin, which is more difficult to clean.

Mild dog bites, causing only superficial scratches without causing bleeding or exposure of the lower layers of the skin, are less worrisome, because the risk of infection is low. To be infection, bacteria must pass through the protective barrier of the skin.

In adults, the sites most commonly attacked by dogs are the hands, arms and legs. Already in children, arms, head and neck are the most affected sites.

In most cases, the bite is caused by a known dog often family itself. Children are the most common victims, as they are more estabanadas have less sense of danger and less able to recognize when a dog is about to attack.

Dog bite infection

The natural bacterial flora of the mouth of the dogs have more than 60 different kinds of bacteria, many of them capable of causing infections in humans. As an example, a dog bite can cause an infection by bacteria following genres:
  • Bacteroides
  • Corynebacterium
  • Clostridium
  • Eikenella
  • Enterobacter
  • Fusobacterium
  • Haemophilus
  • Klebsiella
  • Moraxella
  • Neisseria
  • Pasteurella
  • Porphyromonas
  • Prevotella
  • Proteus
  • Staphylococcus
  • Streptococcus

Generally, an infected dog bite is caused by more than one type of bacteria. Sometimes, for up to 5 kinds of bacteria at the same time. Bacteria called Pasteurella are the most often cause wound infection, being responsible or co - responsible for over 50% of infections.

The symptoms and signs of wound infection usually appear within the first 24 hours, but sometimes, may already occur in the first 8 hours of the bite. Fever, swelling, severe redness, pain, pus drainage, abscess formation or necrosis of the skin are the most common clinical findings.

If not treated properly, the infection of the bite can cause complications such as osteomyelitis (infection of the bone), septic arthritis (joint infection) or tenosynovitis (inflammation of the tendons). In more severe cases, the bacteria can spread into the bloodstream, causing widespread infection and septic shock.

Rabies transmission by dog bite

Rabies is a viral disease that has a mortality rate of almost 100%. There is no effective treatment, but prophylaxis (prevention) is possible through vaccine or immunoglobulin.

Rabies is transmitted through the dog's saliva. The bite is the primary means of inoculation of infected saliva in the human body.

Every individual bitten by a dog must first try to get their vaccination records to see if the animal is properly vaccinated, since vaccinated dogs are not sources of rabies transmission. If the dog is with the vaccine days, no need to start any treatment unless the animal pass to show symptoms of rabies few days after the bite.

In dogs, the maximum time of disease progression, since the appearance of the virus in saliva until his death, is only 10 days. So when someone is bitten by a dog, it indicates the observation of the animal for up to 10 days. If the dog does not get sick in this range is because it was not a contaminant on the bite, there is not therefore any risk of anger for the patient, even if the dog is not with the vaccine on time.

If the animal is a stray dog, ownerless, it is important to capture it so that it can be examined by a veterinarian to look for signs of rabies virus. If the animal's capture is not feasible, prophylactic (preventive) treatment should be given, assuming that this is infected with the rabies virus. Therefore, treatment should be started as soon as possible, as prophylaxis against rabies is considered a medical emergency.

What to do after a dog bite

The first step after a dog bite is vigorously clean the wound area with soap and water for at least 5 minutes. If there is bleeding, the site should be compressed to until the bleeding is staked.

Medical attention should be sought immediately in case of bleeding that does not cease, extensive lesions that need to be sutured, bites with severe lesions of the skin, especially if exposure of internal structures such as muscle, nerves and tendons, bone fracture is suspected, damage to tendons or deep penetrating bites. Injuries that seem to be getting worse with the passage of time should also always be evaluated by doctors.

Antibiotic treatment is indicated in all cases of suspected wound infection. However, in some specific cases, antibiotics can be started prophylactically, that is, before there were clear signs of skin infection. Are they:

  • Sharp and deep wounds.
  • Serious injury with crushing of the affected area.
  • Multiple bites the body.
  • Cancer involving the blood vessels.
  • Bites on the hands, face or genitals.
  • Bites that require suturing.
  • Patients who have have some degree of immunosuppression.

Amoxicillin with clavulanic acid is usually the antibiotic of choice for treating bite infection.

Individuals whose last dose of tetanus vaccine already has more than 10 years should receive a booster dose of the vaccine because Clostridium tetani is a bacteria that can be inoculated through the bite.

If the doctor thinks that the wound could be washed well and there is low risk of infection, the lesion can be sutured. However, there are situations in which the risk of wound infection is very large, and the lesion must be left open to heal naturally. Are they:

  • Bites in the hands or feet.
  • Deep bites.
  • Biting over 12 hours.
  • Bites in immunosuppressed patients.

In these situations mentioned above, the suture the wound may increase the risk of infection, so inadvisable sense.

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