A swollen cat paw is 1 of 3 things: inflammation between the toes, trauma to the pad or nail bed, or a mass. The 3 look similar on day 1 and separate quickly after that. Measure the paw with a tape at 1 cm above the pad, note which of the 4 paws is largest, and give the swelling 24 hours: a paw that is bigger and hotter at 24 hours needs a vet, and a swelling still present at 14 days needs a biopsy, not a fourth course of wipes.
Three checks you can do in 5 minutes
Do all 3 in the same order every day so the numbers compare:
- Measure with a soft tape at 1 cm above the pad, around the widest part. A normal front paw is 8 to 11 cm in circumference on an average 4 to 5 kg cat. Write down all 4 numbers, not just the swollen one.
- Press the swelling with 1 finger for 2 seconds and release. A dent that stays for more than 1 second is pitting edema, which points to fluid rather than to a mass. A firm, non-pitting lump is a different list.
- Spread 2 toes 3 to 5 mm apart and look into the web in daylight. Redness, a 1 to 3 mm sore, brown discharge, or a hair mat packed between the pads is interdigital disease. Compare the same web on the opposite paw.
Interdigital dermatitis: the bilateral clue
Pododermatitis is usually symmetrical and usually affects the front paws first, with 2 to 4 toes involved per paw. Causes stack: a food or environmental allergy, Malassezia yeast, Staphylococcus, a grass awn wedged in the web, or an underlying hormonal problem. Cytology takes 5 minutes and tells yeast from bacteria, which decides whether the plan is antifungal, antibacterial, or neither. A cat that has been chewing and licking for 3 weeks will have thickened, greasy skin between the pads, and that change takes 4 to 8 weeks to reverse even after the cause is controlled.
Trauma: the 24-hour peak
Bites, glass, a nail torn at the quick, and a jump from a height all swell within 2 to 6 hours and peak at 12 to 24 hours. Look for 1 puncture rather than a swollen web, a nail that sits at the wrong angle, or blood on the pad. Cat bites are small on the surface and deep underneath, so a 2 mm hole can hide an abscess that opens 48 hours later; the first 48 hours are the same window described in the swollen-paw timeline. A torn nail that exposes the quick is painful enough to stop all weight bearing and needs same-day care.
Tumor: the 14-day rule
Squamous cell carcinoma of the digit, fibrosarcoma, and mast cell tumor all present as a firm swelling that does not hurt much. The pattern that matters: 1 paw only, 1 toe only, present 14 days or more, no response to 2 weeks of antibiotics. At that point the next step is a 4 to 6 mm punch biopsy under local block or a fine needle aspirate first, then biopsy if the aspirate is not diagnostic. Digital tumors are far more common on the front feet and on cats over 10 years old, and early amputation of 1 digit has a much better outcome than a 6-month delay.
The 24-hour observation protocol
Take 3 numbers at 8 a.m. and 8 p.m.: circumference at the 1 cm mark, pad temperature difference against the opposite paw, and a lameness score 0 to 4, where 0 is normal and 4 means the paw is not touched to the floor. A difference of 2 to 3 C is inflammation. A paw that is cooler than its neighbor, or that is pale and pulpy, means blood flow is the problem and the cat goes in within 1 hour. Swelling that grows 1 cm or more in 24 hours moves the case to the urgent row.
What the vet adds in 20 minutes
Cytology of the web and of any discharge; a Wood lamp is useless here, but a fungal culture takes 10 to 14 days. Two X-ray views separate a foreign body, a bone lesion and a soft-tissue swelling, and cost 40 to 90 dollars. Ultrasound of the pad takes 5 minutes and finds fluid pockets a film misses. A deep wedge or punch biopsy is the only test that answers tumor, and results come back in 3 to 7 days.
When to go: the tier table
Use the worst row that fits. Swelling plus any of the bottom 3 rows is not a wait-and-see case.
| Tier | What you see | Number that decides | Window |
|---|---|---|---|
| Watch | Small web redness, cat walks normally | Under 1 cm of asymmetry, 24 hours old | Recheck in 72 hours |
| Book today | 1 paw, warm, limping, still eating | 2 to 3 C warmer than the other paw | Within 24 hours |
| Urgent | Swelling grew overnight, or a nail is torn | 1 cm or more in 24 hours | Within 12 hours |
| Emergency | Cool, pale paw, cat crying when touched | Cooler than the opposite paw | Now, under 1 hour |
| Biopsy line | 1 toe, 1 paw, no response to treatment | Present 14 days or longer | Book within 7 days |
Home care that does not make it worse
Soak the paw in lukewarm water for 5 minutes twice a day, dry the web with a cloth, and keep it dry between soaks. Change a bandage every 24 to 48 hours and never leave it on more than 72 hours, because a wet bandage under a swollen pad causes more damage than the wound. Use an Elizabethan collar for 10 to 14 days; a cat can undo 3 days of healing in 2 minutes of licking. Clip hair from the web with a 1 mm guard instead of scissors. Stop all paw wipes and human antiseptics, which sting and leave residue. If the cat walked through a spill, a drain cleaner or a floor cleaner can burn a pad as well as a bite can, so check the label against the toxin list before you treat it as an injury.
- Photograph and measure all 4 paws today at the 1 cm mark and keep the numbers in 1 place.
- Check the web on the opposite paw, not just the swollen one; symmetry changes the diagnosis.
- Book the visit if the swelling is 1-sided, 14 days old, or cooler than its neighbor.
- Ask for cytology before antibiotics, so the first treatment is aimed at yeast or bacteria, not guessed.
Terms mentioned in this article
Frequently asked
Is a swollen paw always an infection?
No. Interdigital dermatitis is inflammatory and often allergic, trauma is mechanical, and a tumor is neither. That is why cytology comes before antibiotics: it separates yeast, bacteria and sterile inflammation in about 5 minutes. A paw that has had 2 courses of antibiotics without shrinking is more likely allergic or neoplastic than resistant.
Why biopsy at 14 days instead of waiting longer?
Benign and malignant swellings both stop responding to treatment, and 14 days is long enough for infection or a foreign body to declare itself. A 4 to 6 mm punch biopsy answers the question in 3 to 7 days. On a digit, that delay matters: removing 1 toe early is a much smaller operation than removing 2 or 3 later.
How do I know if the paw is too cold to wait?
Compare it with the opposite paw at the same moment. A difference of 2 to 3 degrees warmer is inflammation and can wait for an appointment. A paw that is cooler than its neighbor, pale, or soft and pulpy suggests impaired blood flow, and that is a 1-hour problem, not a 24-hour one.
Related guides
- Cat Eyelid Swelling: The 2-Hour Line and 3 Don'ts
- Cat Lip Swelling: 24-Hour Line, 5 Causes and Biopsy Rules
- Neck Lump in a Cat: Node, Thyroid, Cyst, or Abscess
- Cat Chewing Its Paws: 4 Causes and a 6-Point Home Check
- Swollen Paw in a Cat: 48-Hour Rule and 3 Causes
- Cat Tail Swelling: 3 Causes, the 5 cm Line, 24 Hours