If your cat is a little feisty when he claws the furniture, or if he is primarily an outdoor cat, keep an eye on his claws. Cats can injure their claws in the same way that humans can rip a fingernail — and sometimes cats' claws can be torn out altogether. If this happens, you can help comfort your kitty until he can be seen by a veterinarian.
Feline Claw Sheaths
When your cat's muscles are relaxed, his claws remain retracted or, more specifically, sheathed. When your cat tenses his muscles, his claws unsheathe and are ready to claw you, the carpet or the mouse he found outside. If you see your cat chewing on his claw, what he's doing is trying to remove the old, worn-out sheath from his paw in order to reveal the newly grown, sharp nail underneath. These sheaths may look like torn-out claws when they fall out, especially if the sheaths fall out while your cat is clawing at his scratching post (or more likely at your furniture). Don't be worried—unless your cat starts to limp, show signs of pain or starts to bleed in one paw, he has most likely not lost a claw, just discarded an old sheath.
If your cat has torn-out a claw, you should be able to tell by observing his behavior. If your cat has a limp or favors one paw when he walks, this can be a sign of injury. Other signs include bleeding or a discharge of pus around the injured claw, or if your cat licks and nibbles repeatedly at the same spot on his paw. The first thing you must do to treat this injury is clean the injured site. Use warm water to flush out the area, and if the area is still bleeding, apply pressure. Avoid using hydrogen peroxide, which can damage healthy tissue, and alcohol, which is very painful on open wounds. If necessary, you can also apply a loose, temporary bandage over the paw until you get to the vet. Kitties are notorious for chewing off bandages, however, so watch him closely so he doesn't ingest any bandage material, which can cause an intestinal obstruction.
If your cat's paw begins to swell, or if the wounded area continues to bleed or shows any sign of pus leaking out, take your cat to the vet — the wound has probably become infected. If the paw feels hot to the touch, or the pad of his paw appears bright red, this can also be a sign of infection. You should take your pet to the vet immediately since he may need medication for infection and pain.
To avoid infection, your cat should stay indoors until his injury heals completely, and you should keep it clean and dry. If your vet applied a bandage, keep your cat from gnawing at his paw as much as possible. You might want to ask your veterinarian about getting an Elizabethan collar for him. This is a large, plastic collar that can be placed around your cat's neck to prevent him from licking his body, specifically the wounded area.