If a cat bites you, wash the wound immediately with soap and running water for at least five minutes, then seek medical attention, especially if the bite is on your hand. Cat bites carry a surprisingly high infection rate: 20% to 50% become infected, far more than dog bites. That small puncture wound may look harmless, but a cat’s narrow, needle-like teeth can push bacteria deep into tissue, joints, and even bone.
Why Cat Bites Are More Dangerous Than They Look
Cat teeth are sharp and thin, almost like hypodermic needles. When a cat bites down, those teeth can puncture deep into tissue while leaving only a tiny mark on the surface. The skin closes over the wound quickly, trapping bacteria in an environment where it thrives. This is fundamentally different from a dog bite, which tends to tear and crush tissue but leaves a more open wound that’s easier to clean.
The real danger is where those teeth can reach. Bites on the hand are particularly risky because the skin there sits close to tendons, joints, and bone. Bacteria can seed directly into a tendon sheath or joint space, where they’re partially shielded from your immune system and blood supply. A Mayo Clinic study found that 1 in 3 patients bitten on the hand required hospitalization, with bites directly over the wrist or finger joints carrying the highest risk.
Immediate First Aid Steps
Start by washing the wound thoroughly with soap and warm running water. Don’t just rinse it briefly. Let the water flow over and into the puncture for several minutes to flush out as much bacteria as possible. If the bite is bleeding mildly, let it bleed for a short time, as this helps push bacteria out of the wound.
After washing, apply an antiseptic if you have one available, then cover the wound with a clean bandage. Avoid sealing it tightly or using butterfly bandages to close the puncture. You want the wound to drain, not trap bacteria inside. Keep the area elevated if the bite is on your hand or arm, as this helps reduce swelling.
When You Need Medical Care
The short answer: almost always. Cat bites that break the skin generally warrant a medical visit, but some situations are more urgent than others.
Get prompt attention if the bite is on your hand, wrist, or near any joint. These locations carry the highest risk of deep infection because bacteria can reach tendons, joint capsules, and bone so easily. Even a pinpoint bite mark in these areas can cause serious problems. You should also be seen quickly if the bite is deep, if you can’t stop the bleeding, or if you have a condition that affects your immune system (diabetes, liver disease, or any immunosuppressive medication).
Timing matters. People who wait more than 8 to 10 hours to get medical attention after a bite are at significantly higher risk for infection. The sooner bacteria are addressed, the better the outcome.
Antibiotics and Preventive Treatment
Doctors frequently prescribe preventive antibiotics for cat bites even before signs of infection appear. A typical preventive course lasts about 3 days, while bites that are already showing signs of infection are treated for 5 to 7 days. The goal is to get ahead of the bacteria before they establish a deeper foothold.
Your doctor will also check your tetanus vaccination status. If you haven’t had a tetanus booster in the past five years and the wound is deep or dirty, you’ll likely need one. For bites from stray or unvaccinated cats, rabies exposure may need to be evaluated as well.
Bacteria That Cause Infections
Cat bite wounds are typically infected by multiple types of bacteria at once, both from the cat’s mouth and from your own skin. The most common culprit is a fast-moving bacterium called Pasteurella, which lives in the mouths of most cats. Pasteurella infections can cause redness, swelling, and intense pain within 12 to 24 hours of the bite, sometimes faster.
Other bacteria found in cat bites include Capnocytophaga species, which typically cause symptoms 3 to 5 days after the bite and can progress rapidly from a mild local infection to a life-threatening systemic illness. People without a spleen are at especially high risk from this organism. Cats can also transmit Bartonella henselae, the bacterium responsible for cat scratch disease, which causes swollen lymph nodes near the bite or scratch site, sometimes weeks after the initial injury.
Signs the Bite Is Getting Infected
Watch the wound closely over the first 24 to 72 hours. Infection can develop fast. Warning signs include:
- Increasing redness that spreads beyond the immediate bite area, especially red streaks traveling up toward your arm or body
- Swelling and warmth around the wound that worsens rather than improves
- Pus or cloudy drainage from the puncture site
- Increased pain that seems disproportionate to the size of the wound
- Fever, chills, or body aches, which suggest the infection may be spreading beyond the local area
- Blisters forming near the bite
Any of these signs, particularly fever or spreading redness, mean you need medical care right away. A bite that looked fine yesterday can become a serious infection overnight.
Serious Complications
When cat bite infections go untreated or progress despite initial treatment, they can lead to deeper problems. Infection of the tendon sheath (tenosynovitis) is one of the more common complications from hand bites. It causes the affected finger to swell along its entire length, become extremely painful with movement, and hold in a slightly bent position. This often requires surgical drainage and IV antibiotics.
If bacteria reach a joint, septic arthritis can develop. If they reach bone, the result is osteomyelitis, a bone infection that’s difficult to treat and may require weeks of antibiotics. In rare cases, bacteria from a cat bite enter the bloodstream and cause sepsis, a body-wide inflammatory response that can lead to organ failure. Capnocytophaga infections in particular can escalate from mild symptoms to septic shock surprisingly quickly.
These outcomes are uncommon when bites are treated promptly, which is exactly why early medical attention matters so much for what seems like a minor wound.