Cat-Scratch Disease
(Editor's note: this page was written with help from
Sniff and
Cat Scan. They
also told me to make sure I told you that cat-scratch disease
is not their fault.)
Cat-scratch disease is an infection with the bacteria Bartonella
henselae. This bug is commonly found in cats, thus the term
"cat-scratch". However, the bacteria is spread between cats
by fleas and ticks, and researchers have recently suggested that
ticks may be able to transmit B. henselae to humans. There
are several other bacteria in the Bartonella family, some of which
behave very much like B. henselae if they infect people.
- (Note from
Cat Scan: so
that's why you give us that stuff every month!
- (Editor's note: she's talking about their flea and tick
medicine.)
- I still don't like it, though. Hmph!)
- (Note from
Sniff: but we like the treats Daddy gives us afterwards...)
Although cats can carry Bartonella, and may have the
bacteria in their blood for weeks to months (sometimes for more
than a year) they don't often have symptoms. Kittens (less than
a year old) are more likely than older cats to have
Bartonella in their blood. Stray cats carry the bacteria
more often than do pet cats, and indoor cats are less likely to
be carriers than outdoor cats.
- (Editor's note to
Cat Scan and
Sniff:
Now do you see why I don't let you out of the house?)
- (Note from
Cat Scan:
You mean it's not because you don't want
Sniff and me
to visit all the birdies outside?)
- (Editor's note to
Cat Scan and
Sniff:
Visit them? Or chase them? And besides, every time Grandma
or Granddad or I open the door you and
Sniff run and hide!)
When we need to test for cat-scratch disease, we look for
antibodies to Bartonella rather than for the bacteria
themselves. About 6% of healthy people have antibodies to
Bartonella. Most people who have signs of infection
are 20 years old or younger. Dogs can also be infected with
Bartonella, as can deer, dogs, cattle, rabbits, rodents,
lions, and even porpoises. Unlike cats, infected dogs often
develop medical problems very like those seen in infected people.
- (Note from
Cat Scan:
That's because we're better than dogs.)
- (Editor's note to
Cat Scan:
Aren't you being a little speciesist?)
- (Note from
Sniff: What's "speciesist", Daddy?)
- (Editor's note to
Sniff:
It's a term that probably would be used by proponents of
political correctitude.)
- (Note from
Cat Scan:
And what's political correctitude?)
- (Editor's note to
Cat Scan:
It's... oh, forget it.)
In most people, the only sign of cat-scratch disease is a
papule (a bump) at the site of the scratch, appearing about
1 to 1-1/2 weeks after the scratch. This papule eventually
turns into a pustule (a bump full of pus). About 1-3
weeks after the initial bump appears, we see swollen glands
near the bump (in the armpit if the arm was scratched, in the
groin if the leg was scratched). We can also see low-grade
fever, malaise
(feeling lousy), and myalgia (aches and pains); sometimes we also
see headaches, loss of appetite, and enlagement of the spleen.
Occasionally an abscess develops in an enlarged lymph node.
Sometimes (in less than 9% of patients) a patient develops
encephalitis
(inflammation of the brain, as opposed to meningitis, which
is inflammation of the membranes covering the brain and spinal
cord), endocarditis (inflammation of the heart walls),
pneumonia, or other problems. Although patients with
encephalitis can have seizures while they are sick, they tend
to recover without long-term problems, and there has been only
one report of a death from cat-scratch related
encephalitis. Usually, people severely ill with cat-scratch
disease have problems with immunity to begin with; these
include very young children, the elderly, and people who are
being treated for cancer.
People with cat-scratch disease usually recover in 2 to 4
months even without treatment. Several
antibiotics,
including
amoxicillin,
trimethoprim/sulfamethoxazole, rifampin,
azithromycin,
ciprofloxacin,
and
tetracycline, will kill Bartonella and can be used to treat
cat-scratch disease; sometimes, an abscess needs to be opened
up and the pus inside drained.
As always, the best treatment is prevention. I do not
recommend avoiding cats entirely,
- (Note from
Cat Scan:
I should certainly hope not!)
although you might want to think twice about cats that do a
lot of scratching or biting if you know you have immune-system
problems. Some authorities recommend that immunocompromised
people should not get a new cat who's less than one year old,
as they are more prone to scratching and biting.
- (Note from
Sniff:
Well, when we were less than 1 year old we didn't scratch
people who treated us properly (like Daddy and Grandma and
Granddad), and we still don't -- especially when they're
giving us treats.)
You should also be diligent about flea treatment for your cat
(they'll thank you for it, too, no matter what
Cat Scan
says).
- (Note from
Cat Scan:
did Daddy just say that it doesn't matter what we say?
I think a little reeducation's in order.)
- (Note from
Sniff: Hmmm... maybe we ought to reconsider not
scratching him.)
- (Editor's note to
Cat Scan and
Sniff:
And were you expecting your bedtime treats tonight?)
- (Note from
Sniff: Uh-oh... )
You should also wash your hand thoroughly with soap and running
water after handling your cats, or taking care of their litter
boxes.
- (Note from
Sniff:
And before and after you feed us, too -- don't forget that.)
- (Editor's note to
Cat Scan and
Sniff:
Don't forget what? Feeding you? You never forget to remind me
-- even when it isn't time!)
- (Note from Sniff:
I meant washing your hands before and after you feed us.)
- (Editor's note to
Cat Scan and
Sniff:
I always do -- even when you and your sister are trying to drink
from the faucet... and, apropos, if your cats drink from the
faucet you should let the water run for a bit before washing
your hands in it -- just on general principles of hygiene.)
If your cat does scratch you, wash the scratched area thoroughly
with soap and running water. Let your doctor know about the scratch
if any papules, pustules, or swollen glands appear, especially if
you have immune-system problems.
- (Note from
Cat Scan:
And if your cats scratched you because you made them mad at you,
make sure you tell them you're sorry -- that's very important,
too.)
-
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We welcome your
comments and questions.
PLEASE NOTE: As with all of this Web site, I try to give
general answers to common questions my patients and their parents ask me
in my (real) office. If you have specific questions about your
child you must ask your child's regular doctor. No doctor can give
completely accurate advice about a particular child without knowing and
examining that child. I will be happy to try and answer
general questions
about children's health, but unless your child is a regular patient of
mine I cannot give you specific advice. (And
Cat Scan and
Sniff don't let
me try to give advice on cat health.)
Copyright © 2006, 2007
Cat Scan, Sniff, and Vinay N. Reddy, M.D. All rights reserved.
Written 03/29/06; major revision (mostly by
Cat Scan) 01/21/07;
last revised 10/11/07
