About 1 in 5 dog bites becomes infected. Some of those infections turn into medical emergencies within hours. Knowing the warning signs of a dog bite infection — and when to get to an ER — can protect you from much worse outcomes.
This guide covers what to do right after a bite, what infection looks like, and which symptoms mean you need emergency care now.
Why Dog Bites Get Infected So Easily
A dog's mouth carries more than 64 species of bacteria. When a dog bites, those bacteria get pushed into the wound — especially in puncture bites, where the skin seals shut over the bacteria and traps them beneath the surface.
Two bacteria are responsible for most serious dog bite infections:
Pasteurella multocida — Present in roughly 50% of infected dog bite wounds. It causes rapid swelling, redness, and pus, sometimes within 24 hours of the bite.
Capnocytophaga canimorsus — Present in healthy dogs' saliva. Most people clear it without problems. But in people with weak immune systems, it can cause a severe, life-threatening infection. The CDC reports a case-fatality ratio ranging from 26% to 33% in serious Capnocytophaga cases.
Dog bites also introduce Staphylococcus and Streptococcus bacteria, common causes of skin infections.
People at highest risk for a serious dog bite infection:
- People with diabetes
- Those taking steroids or immune-suppressing medications
- Cancer patients on chemotherapy
- People whose spleen has been removed
- Adults over 65
- People with HIV or other immune conditions
If any of these apply to you, get medical attention after any dog bite that breaks the skin — even a minor one.
What to Do Right After a Dog Bite
Acting quickly cuts the risk of infection. Here is the order of steps.
Step 1: Stop the Bleeding
Press a clean cloth or sterile gauze firmly against the wound. Keep steady pressure on it. Elevate the injured area above heart level if you can.
Step 2: Wash the Wound — the Most Important Step in Dog Bite Wound Care
Put the wound under lukewarm running water. Wash with mild soap for a full five to ten minutes. Let the water flow through the wound to flush out bacteria before they anchor into tissue.
Skip hydrogen peroxide and alcohol. Both damage tissue and slow healing. Soap and water work better.
Step 3: Apply Antibiotic Ointment
Put a thin layer of over-the-counter antibiotic ointment (Neosporin or Bacitracin) on the wound. This slows bacterial growth while the wound begins to close.
Step 4: Cover It Up
Cover with a clean sterile bandage. Change the dressing daily, or right away if it gets wet or dirty.
Step 5: Watch the Wound Closely
Check it every few hours during the first 48 hours. Know what an infected wound looks like — that is the next section.
Step 6: See a Doctor Within 8 Hours for Deep or Puncture Bites
Minor scrapes can be watched at home. But deep bites, puncture wounds, bites near joints, and any bite on the face, hand, or foot need a doctor within 8 hours. The longer you wait, the higher the infection risk.
A doctor will clean the wound properly, may prescribe preventive antibiotics, check your tetanus status, and decide whether rabies post-exposure shots are needed.
Signs of Infected Dog Bite: What to Watch For
Dog bite infection symptoms can show up as early as 12 to 24 hours after a bite, or take 3 to 5 days depending on which bacteria are involved.
Watch for these signs of infected dog bite:
- Redness spreading past the wound edges
- Swelling that keeps getting worse instead of improving
- Warmth or heat at the bite site
- Pain that gets worse, not better
- Pus or cloudy discharge coming from the wound
- Foul smell from the wound
- Fever above 101°F
- Swollen lymph nodes near the bite (armpit for a hand bite, groin for a leg bite)
One sign that needs emergency care right now:
Red streaks extending from the wound. These streaks travel along lymphatic channels and mean the infection is spreading fast through your body. Do not call urgent care. Go to the ER.
When to Worry: Dog Bite Infection Emergency Signs
Some situations cannot wait for an urgent care appointment.
Go to the ER or call 911 immediately if:
- Red streaks are spreading from the bite
- You have a fever over 101°F along with confusion, fast heartbeat, or extreme weakness — these are signs of sepsis
- The wound is deep enough to expose bone, tendon, or muscle
- Bleeding will not stop after 15 minutes of pressure
- The bite is on your face, near your eye, or on your neck
- You are immunocompromised and the bite broke the skin
Go to urgent care or your doctor within 8 hours if:
- The bite is a deep puncture wound
- The bite is on your hands, feet, or over a joint
- The dog was a stray or its vaccination history is unknown
- Your last tetanus shot was more than 5 years ago
- Infection signs appear — redness, swelling, pus — at any point
About sepsis: Sepsis is a dangerous, whole-body reaction to infection. It can develop within hours of an untreated dog bite infection. A person may feel only mildly ill in the morning and need an ICU by evening. If someone becomes confused, stops urinating, develops a very high or very low temperature, or has a racing pulse after a dog bite — call 911.
What Happens If You Ignore an Infected Dog Bite
Untreated dog bite infections can lead to:
Cellulitis — A bacterial skin infection that spreads into deeper tissue. The affected area becomes red, swollen, and tender. It requires prescription antibiotics and sometimes hospitalization.
Sepsis — Bacteria enter the bloodstream and trigger organ failure. Rare from dog bites, but documented and potentially fatal.
Osteomyelitis — Bone infection. More common with deep puncture wounds near joints, where bacteria can reach bone directly.
Tenosynovitis — Infection of the tendon sheath, particularly in the hand. This often requires surgery.
Rabies — Extremely rare from domestic US dogs due to vaccination requirements. The risk is real, though, with stray dogs or dogs from abroad. Rabies is nearly always fatal once symptoms appear — but post-exposure shots started promptly are almost 100% effective at preventing it.
Tetanus — A deep puncture wound can introduce tetanus bacteria. A routine booster every 10 years protects against tetanus, but for contaminated wounds such as dog bites, doctors may recommend a booster if your last one was more than 5 years ago.
A Note on Rabies After a Dog Bite
Most dogs in New York are vaccinated against rabies, and rabies from domestic dogs is very rare. Still, some steps are worth taking:
- Find out who owns the dog. New York State public health law requires a 10-day confinement and observation period for the biting animal so authorities can confirm it was not shedding rabies virus.
- If the dog was a stray or unvaccinated, talk to your doctor or local health department about post-exposure shots.
- For any bite from a bat or wild animal (raccoon, fox, skunk), go to the ER for rabies evaluation regardless of how minor the bite looks.
- Post-exposure shots work — they are given over 14 days and are highly effective when started quickly.
If you are unsure about rabies risk, call your local health department or ER for guidance. It is a call worth making.
Frequently Asked Questions About Dog Bite Infections
How do you know if a dog bite is infected?
Signs of a dog bite infection include redness spreading beyond the wound, swelling that worsens after the first day, pus or foul-smelling discharge, and fever above 101°F. Pain that increases instead of easing is also a reliable sign. Red streaks extending from the wound are a serious warning — go to the ER immediately.
How long does it take for a dog bite to get infected?
Some infections appear within 12 to 24 hours, particularly with Pasteurella bacteria. Others, like those caused by Capnocytophaga, may take 3 to 5 days to show symptoms. Watch the wound closely for at least a week after the bite.
What happens if you don't treat an infected dog bite?
An untreated infection can spread into deeper tissue (cellulitis), reach the bone (osteomyelitis), infect the tendon sheath (tenosynovitis), or progress to sepsis — a life-threatening infection of the bloodstream.
Should I go to the ER for a dog bite?
Go to the ER for red streaks from the wound, fever with confusion or rapid heart rate, a bite exposing bone or tendon, or if you are immunocompromised. For other bites that break the skin, see a doctor within 8 hours.
What bacteria is in a dog bite wound?
Dog bites commonly carry Pasteurella multocida (in about 50% of infected wounds), Capnocytophaga canimorsus, Staphylococcus, and Streptococcus. Most dog bite infections involve more than one type of bacteria.
Can a dog bite cause sepsis?
Yes. Untreated dog bite infections can progress to sepsis. Capnocytophaga canimorsus is one bacteria linked to severe systemic infections with reported fatality rates of 26% to 33% in serious cases. Sepsis can develop within hours and is a medical emergency.
How do you treat an infected dog bite at home?
For early, mild redness with no fever or pus, keep the wound clean, apply antibiotic ointment, and change the dressing daily. If you see spreading redness, swelling, pus, or any fever — see a doctor. Do not try to manage a moderate or severe infection without medical care.
Sources & Official Resources
Federal Health Resources
- CDC — About Capnocytophaga
- CDC — Capnocytophaga Clinical Overview
- CDC — Zoonotic Exposures: Bites, Stings, Scratches (Yellow Book 2024)
- CDC — Clinical Guidance for Wound Management to Prevent Tetanus
- CDC MMWR — Nonfatal Dog Bite–Related Injuries, United States, 2001
New York State Health Resources 6. NYS Department of Health — Rabies Guidance & Regulations 7. NYS Department of Health — 10-Day Confinement Guidance
Peer-Reviewed Research 8. NIH/PMC — Animal Bites Treatment Protocol 9. CDC Emerging Infectious Diseases — Diagnosing Capnocytophaga canimorsus Infections
Contact The Orlow Firm
Dog bites cause real physical harm. When someone else's dog injures you, New York law may hold the owner responsible for your medical bills, lost wages, and other losses. If you want to understand your legal options, our Queens dog bite attorneys can walk you through them at no charge.
The Orlow Firm has handled personal injury cases in New York since 1982. Call (646) 647-3398 for a free consultation. Se Habla Español.
The information on this page is for general educational purposes only and is not legal or medical advice. For a medical emergency, call 911.
