Dear Straight Dope:
Having just entered the full-time position of "cat-owner" I have found that uninvited snuggling seems to invariably lead to an armed response on the part of my cat. The scratches immediately swell or turn an ugly shade of red, and my S.O. claims that cats actually have poison sacs in their claws and that this poison causes the ugly discoloration and swelling. So the question is, do cats have poison claws?
I once worked as a veterinary assistant and came to the conclusion that cats are walking infections. Not just for people, but for each other, too. Seems like almost every cat brought into the clinic after being beat up in a catfight had wounds that were not only quickly infected, they were necrotic (that is, the surrounding tissue was dead). Eww. I remember working on a cat once while the veterinarian stood nearby eating a pastrami sandwich. He was recounting the details of a procedure in which he had his arm up to the elbow in a horse’s anus while I severed the rotting gray meat from around a shoulder wound on a big, matted cat. What a cornucopia for the senses that was.
But no, cats don’t have poison claws. Most likely you are simply allergic to cats. Saliva on their paws can cause this reaction in allergic persons. Some cats (mostly kittens) do carry a bacteria in their saliva called Bartonella henselae which can cause "cat scratch disease" in people. As the name suggests, the disease results from the scratch or bite–or even the lick–of an infected cat, though the cats themselves suffer no symptoms (of course). The bacteria is apparently spread cat to cat via fleas, but the fleas don’t transmit it directly to people.
The signs of this disease in humans are local inflammation and redness like you describe, then blisters sometimes at the site and characteristically within two weeks swollen lymph nodes closest to the wound. Some people get a low fever, fatigue, headache, loss of appetite and the desire to drop kick the cat through the picture window.
If you don’t have swollen glands, you probably don’t have this disease, which is actually fairly uncommon. If you’re unsure, a blood test by your doctor will confirm it. The disease usually resolves by itself in a few weeks, and if there is continued pain and discomfort sometimes antibiotics are prescribed.
Whether you have this disease or not, it makes sense to immediately clean any scratches or bites you get from animals. You might also consider de-clawing your cat, though many people frown on this practice as being cruel. For prevention of cat scratch disease, one source I read said, "Steps to minimize scratching and biting should be taken." I recommend duct tape. Wrapped round and round, starting just below the eyes and ending at the base of the tail.
On second thought, get the base of the tail pretty good too. Cat droppings are also a source of infection, notably toxoplasmosis, caused by Toxoplasma gondii, an intracellular coccidian protozoan. Most cat owners acquired the disease from their pets but were asymptomatic and are now immune (it’s not spread person to person). The two groups that have to watch out are immunocompromised individuals, such as people with AIDS–who can develop cerebral toxoplasmosis–and pregnant women, who may pass the disease on to their unborn babies with possibly catastrophic consequences. On the bright side, for these groups toxo does give you an excuse to get out of changing the litter box.
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