When a dog bites you, the immediate damage depends on how hard the bite was, but what happens in the hours and days afterward matters just as much. Dog bites carry a 2% to 25% risk of infection, and the steps you take in the first few minutes can significantly change your outcome. Here’s what actually happens to your body and what you need to do about it.
The Physical Damage
Dog jaws exert enough force to cause several types of injury at once. A bite can create puncture wounds where the teeth sink straight in, lacerations where the skin tears in jagged lines, or crushing injuries to the tissue underneath. Many bites combine all three. Puncture wounds are deceptively dangerous because the small opening on the surface hides deeper damage below, and the narrow channel makes it harder to clean out bacteria.
Bites deeper than about 6.5 millimeters (a quarter inch), bites with jagged edges, or wounds that gape open are more serious and generally need professional wound care. Location matters too. Bites to the hands, fingers, and feet are especially prone to infection because these areas have tendons and joints close to the surface. Bites to the face and neck are concerning in children because of proximity to critical structures.
What’s in a Dog’s Mouth
A dog’s mouth carries dozens of bacterial species, and a bite injects them deep into your tissue. The most common culprit behind infections is a bacterium called Pasteurella, which can cause rapid redness, swelling, and pain within 24 hours. Another group of bacteria, Capnocytophaga, is less common but far more dangerous. It can enter the bloodstream and lead to sepsis, kidney failure, heart inflammation, or gangrene. In severe cases, people have lost fingers, toes, or limbs to Capnocytophaga infections.
People with weakened immune systems, those without a spleen, heavy alcohol users, and anyone on medications that suppress the immune system face a higher risk of these serious complications. But healthy people can develop infections too, which is why proper wound care matters for everyone.
How to Clean the Wound Immediately
The single most important thing you can do after a dog bite is wash it with soap and running water for at least five minutes. Use pressure from the faucet to flush bacteria out of the wound. Don’t scrub the tissue, as that causes additional bruising and damage. After washing, apply an antiseptic lotion or cream.
For shallow bites from a vaccinated household pet, thorough washing at home may be sufficient. For deeper punctures, bites from unknown or unvaccinated dogs, bites to the hands or face, or any wound that won’t stop bleeding, you need medical attention. Research shows that people who reach an emergency room within eight hours of the bite are significantly less likely to develop an infection.
What Happens at the Doctor’s Office
A doctor will irrigate the wound more thoroughly, often with a pressurized saline solution, and remove any damaged tissue. This aggressive cleaning is the foundation of treatment. Whether the wound gets stitched closed depends on its location and infection risk. Facial bites are typically sutured to minimize scarring, but bites on other parts of the body are often left open initially and closed a few days later once the risk of trapping bacteria inside has passed.
For high-risk wounds, doctors prescribe a course of preventive antibiotics, typically lasting three to five days. If you haven’t had a tetanus shot in the past five years and the wound is deep or dirty, you’ll need a booster within 48 hours. Rabies is also on the table: if the dog’s vaccination status is unknown or the animal was behaving strangely, your doctor will coordinate with public health officials to determine whether you need rabies post-exposure treatment, which involves a series of injections.
Signs of Infection to Watch For
Even with proper cleaning, infections can develop. Watch the wound closely for the first several days. Increasing redness that spreads outward from the bite, swelling, warmth, worsening pain, pus or cloudy drainage, red streaks running away from the wound, or fever all signal an infection taking hold. Pasteurella infections tend to show up fast, often within 12 to 24 hours. Other bacterial infections may take two to three days to become obvious.
If an infection does develop, it typically resolves within 10 days with appropriate antibiotics and additional wound cleaning. But ignoring the signs and delaying treatment gives bacteria time to spread into deeper tissues or the bloodstream, where they become much harder to control.
How Long Healing Takes
Recovery time varies based on wound size, whether it was closed with stitches, and whether infection develops. In one clinical study, non-infected wounds that were sutured closed healed in an average of 6.6 days, while similar wounds left open took about 9.1 days. Infection slowed things down: infected closed wounds averaged 10.7 days to heal, and infected open wounds took about 14.2 days.
Scarring depends on several factors. Larger wounds leave more noticeable scars regardless of treatment. Wounds that become infected produce worse cosmetic results than those that stay clean. Facial wounds that are sutured tend to heal with the least visible scarring. For bites on the arms, legs, or trunk, the final appearance of the scar depends heavily on how well the wound was cleaned, whether infection was prevented, and individual healing tendencies.
Reporting the Bite
Most jurisdictions require that dog bites be reported to local health authorities. This isn’t just a legal formality. The report helps public health officials track the dog, confirm its rabies vaccination status, and determine whether the animal needs to be observed for signs of disease, which directly affects whether you need rabies treatment. If you’re bitten by an unknown dog or a stray, reporting is especially important because there’s no owner to confirm vaccination history.
In many cities, dogs are required to be licensed, leashed in public (typically on a leash no longer than six feet), and vaccinated against rabies by four months of age. Dog owners can face legal consequences when their animal bites someone, particularly if the dog was off-leash or had a history of aggression.