A cat bite leaves a hole 1–2 mm across and 1–2 cm deep, and the skin seals over it within 6–12 hours. That closed hole is the problem: cat teeth inject bacteria past the skin barrier into fat, tendon sheath and bone, and up to 80 % of bite wounds become infected without treatment. A 3 cm surgical incision is cleaner than a 2 mm puncture. Flush for 5 minutes, get an antibiotic decision inside 24 hours, and treat a bite over a joint as an emergency on its own.
Why a 2 mm hole beats a 3 cm cut
Cat canine teeth are curved needles. They push oral bacteria — Pasteurella multocida sits in most cat mouths — 1–2 cm under the skin, then the elastic skin closes behind the tooth and traps the load in a low-oxygen pocket. Surface lacerations drain and stay near 5–10 % infection rates; puncture wounds sit near 80 %. Depth also decides the tissue: a bite over the carpus, tarsus or a toe reaches tendon sheath and joint capsule, where infection destroys cartilage in 24–48 hours. An abscess declares itself at 48–96 hours as a hot, painful swelling that ruptures and drains.
On-scene handling: flush for 5 full minutes
Clip hair 2–3 cm around the wound with scissors, then flush with 0.9 % saline or clean tap water at 20–25 °C. Use a 10–20 mL syringe without a needle, held 2–3 cm from the hole, and push 50–250 mL through it over a full 5 minutes by the clock. Flushing dilutes the bacterial load and lifts debris out; nothing else you do at home changes the outcome as much. If the wound is bleeding, let it bleed for 1–2 minutes before flushing, then press sterile gauze for 5 minutes. Bleeding that has not stopped after 5 minutes of steady pressure, or that soaks a gauze pad in under 60 seconds, needs a clinic. This is not the same protocol as caring for a catheter site or a drain at home, which has its own rules in our catheter aftercare guide.
What not to put in the wound
No 3 % hydrogen peroxide, no rubbing alcohol, no iodine poured into the tract: all three damage the tissue that has to heal and push healing back 2–4 days without killing the bacteria that matter. Do not squeeze or probe the hole either; a cotton bud pushed 1 cm deeper can seed a tendon sheath. Do not cover a puncture with a tight bandage or ointment plug, because sealing the surface feeds the anaerobic pocket. Leave it open, cover it loosely with sterile gauze only for the car ride. If the cat licked or ate anything during the fight — a plant, a bait block, a spilled pill — check it against the toxin lookup tool before you leave.
When to drive: minute-level thresholds
Call ahead and say the numbers: bite at 19:05, puncture 1.5 cm deep over the hock, cat 4.2 kg, vaccinated 8 months ago. These match emergency-vet practice. Any bite over a joint, tendon, chest, belly, neck or eye goes in the next 30 minutes; a bite from an unknown or unvaccinated cat goes within 2 hours, because rabies decisions are time-bound. A puncture deeper than 1 cm, a wound that is already 24 hours old, or spreading redness past 2 cm in 6 hours all mean go, not wait. Book same-day if the cat is eating but has a 39.5 °C fever, a resting breathing rate over 40, or a limp on the bitten leg. Kittens under 12 weeks and cats on steroids or with diabetes move to the front of the queue, since their infection risk is 2–3 times higher.
The 24-hour antibiotic window
Antibiotics work best started within 2 hours of the bite, and the window closes at 24 hours; after that, a vet usually cultures the tract before choosing a drug. The common prescription range for amoxicillin-clavulanate in cats is 12.5–25 mg per kg every 12 hours, and clindamycin at 5–11 mg per kg every 12 hours when bone is involved. Those ranges are reference figures from veterinary formularies, not a dose to copy: the actual amount depends on weight, kidney values and whether the cat is pregnant, and it is given on prescription only. Never use leftover human antibiotics. If a vet places a drain, check the site every 4–6 hours and record output.
| Clock time | Action | Numbers to record |
|---|---|---|
| 0–5 min | Clip hair, flush with saline, apply pressure if bleeding | 50–250 mL flush, bleed stop under 5 min |
| 5–30 min | Photograph the wound, call the clinic, glove up | Depth 1–2 cm, hole 1–2 mm |
| 30–120 min | Drive in for a joint, chest or eye bite | Temp 38.1–39.2 °C, pulse 140–220 |
| 2–6 h | Vet clean-out, drain if needed, first antibiotic dose | Dose by mg/kg, weight to 0.1 kg |
| 12–24 h | Re-check redness and swelling at home | Redness under 2 cm, temp under 39.5 °C |
| 48–96 h | Abscess peak: feel for a hot soft lump | Lump over 1 cm means re-check |
What to carry and how to keep it warm
Take 2 sterile gauze pads, a roll of self-adhesive bandage, a 20 mL syringe, 500 mL of 0.9 % saline, gloves, the vaccination card, and a phone photo of the wound with a coin beside it for scale. Use a hard carrier with a towel, not a soft bag, and cover the wound loosely with gauze for the drive. Keep the car at 22–24 °C: a cat arriving at 37 °C core temperature heals more slowly and carries a higher anesthesia risk than one at 38.5 °C. A foil blanket over the carrier holds heat without pressing on the bite. Do not put a hot water bottle against the leg, because heat over an infected puncture increases swelling and bacterial growth, and cat skin burns at 44–49 °C. If the cat is shivering and pale, warm the car.
First 48 hours at home
Photograph the wound at 0, 12, 24 and 48 hours under the same light, and measure the red zone with a ruler each time. A red margin that grows past 2 cm, a temperature over 39.5 °C, a cat that stops eating for 24 hours, or a leg that is more swollen at hour 24 than at hour 6 means the antibiotic is not working and the cat needs a re-check the same day. Expect 3–7 days of antibiotics for a shallow bite and 10–14 days if a joint or tendon was involved; stopping at day 3 because the swelling went down is how abscesses come back. Licking is the main home failure: an Elizabethan collar for 7–10 days beats a reopened wound.
Executable checklist
- Clip, then flush 50–250 mL of 20–25 °C saline over a full 5 minutes.
- No peroxide, alcohol or iodine in the tract, and no tight bandage over the hole.
- Joint, chest, neck or eye bite: clinic in 30 minutes; unknown cat: within 2 hours.
- Antibiotic decision inside 24 hours, ideally inside 2, on prescription by mg/kg.
- Photograph and measure the red zone at 0, 12, 24 and 48 hours.
Terms mentioned in this article
Frequently asked
The bite is tiny and already scabbed. Can I just watch it?
No. The surface closing is exactly what makes a cat bite dangerous, because the bacteria sit 1 to 2 cm deep in a sealed pocket with no drainage. Up to 80 % of untreated bite wounds infect, and an abscess usually appears at 48 to 96 hours. Flush for 5 minutes, photograph the wound, and get a veterinary opinion inside 24 hours even if the cat is behaving normally.
Is 24 hours really the limit for antibiotics?
It is the practical window. Starting within 2 hours gives the best result, and most vets will still start antibiotics at 24 hours but often culture the tract first. Past 24 hours the infection has usually spread into tissue that antibiotics reach poorly, so a drain or surgical clean-out is more likely. Any bite over a joint or tendon skips the window entirely and goes in today.
How do I know the wound is getting worse rather than healing?
Measure, do not eyeball. Trace the red margin and record it at 0, 12, 24 and 48 hours; a margin growing past 2 cm, a temperature over 39.5 °C, a swelling that is larger at hour 24 than at hour 6, or a cat that stops eating for 24 hours all mean the antibiotic is failing. Clear fluid weeping from the hole at 72 hours usually means an abscess is forming under the skin.