Cat Scratch Disease

ExitCare ImageCats often injure people by scratching or biting. This site of injury can become infected with a particular germ or bacteria present in the mouth of or on the cat. This germ is called Bartonella henselae. This infection is identified by the common name cat scratch disease (CSD).


  • A red and sore pimple or bump, with or without pus, on the skin where the cat scratched or bit. The pimple or sore may be present for as long as three weeks after the scratch or bite occurred.

  • One or more enlarged lymph glands located toward the center of the body from where the injury occurred.

  • Less common symptoms include low-grade fever, tiredness, fatigue, headache and/or sore throat.


  • The diagnosis is typically made by your caregiver who notes the history of a scratch or bite from a cat, and finds the skin sore and swollen lymph glands in the described area.

  • Culture of any drainage or pus from the injury site, or a needle aspiration or piece of tissue (biopsy) from a swollen lymph gland may also be done to confirm the diagnosis and assure that a different infection or disease is not causing your illness.

Rare but serious complications may occur, they include:

  • Parinaud's syndrome - fever, swollen lymph glands and inflammation of the eye (conjunctivitis).

  • Infection of the brain (encephalitis).

  • Infection of the nerve of the eye (neuroretinitis).

  • Infection of the bone (osteomyelitis).


  • Usually treatment is not necessary or helpful, especially if you have a normal immune system. When infection is very severe, it may be treated with a medicine that kills the bacteria (antibiotic).

  • People with immune system problems (such as having AIDS or an organ transplant, or being on steroids or other immune modifying drugs) should be treated with antibiotics.


  • Avoid injury while playing with cats.

  • Wash well after playing with cats.

  • Do not let your cat lick sores on your body.

  • Do not let your cat roam around outside of your house.

  • Keep the area of the cat scratch clean. Wash it with soap and water or apply an antiseptic solution such as povidone iodine.

  • You should get a tetanus shot if you have not had one in the past 5 or 10 years. If you receive one, your arm may get swollen and red and warm to the touch at the shot site. This is a common response to the medication in the shot. If you did not receive a tetanus shot here because you did not recall when your last one was given, make sure to check with your caregiver's office and determine if one is needed. Generally, for a "dirty" wound, you should receive a tetanus booster if you have not had one in the last five years. If you have a "clean" wound, you should receive a tetanus booster if you have not had one in the last ten years.


  • You have worsening signs of infection, such as more redness, increased pain, red streaking or pus coming from the wound, or warmth or swelling around the area of the scratch.

  • You develop worsening swollen lymph glands.

  • You develop abdominal pain, have problems with your vision or develop a skin rash.

  • You have a fever.

  • You become more tired or dizzy, or have a worsening headache.

  • You develop inflammation of your eye or have increasing vision problems.

  • You have pain in one of your bones.

  • You develop a stiff neck.

  • You pass out.


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.