Amoxicillin-clavulanate is the first-line antibiotic for cat bites, used both to prevent infection in fresh wounds and to treat infections that have already started. Cat bites carry a notably high infection risk because cats have long, narrow teeth that puncture deep into tissue, depositing bacteria into spaces that are hard to clean and heal slowly. Signs of infection can appear within hours, so getting medical attention quickly matters more with cat bites than with most other animal bites.
Why Cat Bites Are High Risk
The primary bacterium behind cat bite infections is Pasteurella multocida, which lives in the mouths of most healthy cats. This organism thrives in the warm, low-oxygen environment created by a deep puncture wound. Unlike the wider, tearing wounds dogs tend to inflict, a cat’s thin teeth create narrow channels that seal over quickly on the surface, trapping bacteria underneath. That’s why cat bite infections often develop faster, with a median onset of about 12 hours, and sometimes within just a few hours of the bite.
Cat bites also frequently land on the hands and fingers, where tendons, joints, and bones sit close to the skin surface. A tooth that reaches a tendon sheath or joint capsule can seed an infection that’s far more serious than a simple skin infection. These deeper infections sometimes require IV antibiotics or even surgery to resolve.
First-Line Treatment: Amoxicillin-Clavulanate
Amoxicillin-clavulanate (the brand name is Augmentin) covers the full range of bacteria typically found in cat bites, including both the aerobic bacteria like Pasteurella and the anaerobic bacteria that grow in oxygen-poor puncture wounds. It’s effective as prophylaxis for a fresh bite and as treatment for an established infection. A typical course runs 5 to 7 days for prophylaxis and up to 10 to 14 days for active infections, though your prescriber will tailor this based on the wound.
Alternatives for Penicillin Allergies
If you’re allergic to penicillin, the options usually involve combining two antibiotics to cover the same spectrum. Common alternatives for adults include:
- Doxycycline taken twice daily, which covers Pasteurella on its own
- Clindamycin plus ciprofloxacin, a combination that covers both anaerobic and aerobic bacteria
- Trimethoprim-sulfamethoxazole (Bactrim), sometimes paired with clindamycin or metronidazole for broader coverage
For children with penicillin allergies, the typical combination is clindamycin plus trimethoprim-sulfamethoxazole. Pregnant women who can’t take penicillin may be prescribed azithromycin, though it has a higher failure rate and requires close monitoring.
Immediate Wound Care Before Antibiotics
What you do in the first minutes after a cat bite matters. Thorough cleaning is the single most effective way to reduce infection risk, and it starts before you ever see a doctor.
Wash the wound with soap and running water for at least five minutes. Tap water works just as well as sterile saline for irrigation. If you have povidone-iodine (Betadine) available, you can dilute it and use it to rinse the wound, which is especially useful if there’s any concern about rabies exposure. The goal is to physically flush bacteria out of the wound.
The challenge with cat bites is that small puncture wounds are difficult to irrigate thoroughly. In a clinical setting, a doctor may actually open a narrow puncture wound slightly with a scalpel to allow better cleaning, then leave it open to heal from the inside out rather than stitching it closed. Closing a cat bite wound traps bacteria and increases infection risk, which is why most cat bite punctures are deliberately left open.
The Eight-Hour Window
Medical guidelines recommend seeking professional treatment within eight hours of a cat bite to significantly reduce infection risk. Prophylactic antibiotics are generally prescribed when you’re seen within this window, especially for bites on the hands, feet, or face, or any bite that appears deep. If you wait longer than eight hours, infection is more likely to have already taken hold, and your doctor will evaluate whether you need a longer or more aggressive antibiotic course.
Because Pasteurella infections can become apparent within just a few hours, don’t assume a bite is fine simply because it looks small. A cat tooth only needs to penetrate a centimeter or two to reach a tendon sheath in your hand.
Signs the Infection Is Getting Worse
Even with antibiotics, you should watch the wound closely. Redness spreading outward from the bite, increasing pain or swelling, warmth around the wound, red streaking up the arm or leg, fever, and pus or cloudy drainage are all signs that the infection is progressing despite treatment. Pain that seems disproportionate to the size of the wound, particularly in a finger or hand, can signal a deep infection involving a tendon sheath or joint. This type of infection escalates quickly and often needs hospital-level treatment.
Cat Scratch Disease: A Different Infection
Not every infection from a cat involves the same bacteria. Cat scratch disease, caused by a different organism called Bartonella henselae, typically develops 3 to 10 days after a scratch or bite. Its hallmark signs are swollen, painful lymph nodes (usually near the armpit or neck, depending on where the wound is) and small bumps or a rash near the wound site. You might also notice fatigue, low-grade fever, or muscle and joint aches.
Cat scratch disease is generally milder than a Pasteurella wound infection and often resolves on its own, though antibiotics can speed recovery. The key difference is the timeline and the lymph node involvement. A Pasteurella infection shows up within hours as local wound redness and swelling. Cat scratch disease shows up days later with swollen glands that may be far from the bite itself.
Tetanus and Rabies Considerations
Your doctor will also check whether you need a tetanus booster. If it’s been more than five years since your last tetanus shot, you’ll typically get one at the time of treatment.
Rabies is rare in domestic cats in the United States, but it’s always considered after any animal bite. If the cat is a known pet with current vaccinations, rabies prophylaxis usually isn’t needed. If the cat is a stray, feral, or behaving unusually, or if it can’t be observed for 10 days, your doctor may recommend rabies post-exposure prophylaxis. This consists of a dose of rabies immune globulin injected around the wound plus a series of four vaccine doses spread over two weeks. There are no contraindications to rabies vaccination, and pregnancy is not a reason to skip it if exposure is suspected.