What is cat-scratch disease?

Cat-scratch disease (CSD), also known as cat scratch fever, is a bacterial infection spread by cats. The condition is caused by the bacterium Bartonella henselae, which 40 percent of felines carry in their mouths and under their claws.

Cats acquire the bacteria by scratching at or biting infected fleas and from fighting with other cats that may have CSD.

CSD occurs as a result of scratches or bites from domestic or feral cats, especially kittens, that break the surface of the skin, allowing the bacteria to enter a person’s body. If an infected cat licks someone’s open wound, sore or scab, this can also lead to infection.

According to the Centers for Disease Control and Prevention (CDC), an estimated 12,000 Americans are diagnosed with CSD and 500 people are hospitalized with the condition each year. In the United States, most cases of CSD occur in the fall and winter.

What are the symptoms of cat-scratch disease?

Symptoms of CSD usually appear three to 14 days after the skin is broken. The first sign is a red bump, sore or blister with raised lesions at the initial site of the scratch or bite that sometimes contain pus.

Even if the bump heals, other symptoms, such as fever, headache, fatigue, poor appetite and swollen lymph nodes, can appear.

Additionally, CSD can cause serious complications that affect the brain, eyes, heart or other internal organs.

Who is at risk for cat-scratch disease?

CSD incidence is highest among those who live in the southern United States and among children between 5 to 9 years old. But anyone who owns or interacts with a cat is at risk of contracting cat-scratch fever.

What’s more, the CDC reports that patients hospitalized for CSD are more likely to be male and between ages 50 to 64.

People with weakened immune systems and children younger than 5 years old are more likely to have serious complications as a result of CSD.

How is cat-scratch disease diagnosed?

Frequently, doctors diagnose CSD by examining a person’s symptoms. Other methods of diagnosis include testing the blood and checking a tissue sample from an individual’s lymph node.

How is cat-scratch disease treated?

Usually, CSD resolves without treatment. But for those with moderate to severe symptoms, doctors prescribe an antibiotic.

In addition, perhaps the best way to treat cat-scratch disease is to prevent the infection from occurring in the first place. Here’s what the CDC recommends:

  • Wash cat bites and scratches immediately with soap and running water.
  • Don’t pet or touch stray or feral cats.
  • Wash your hands with soap and running water after playing with your cat, especially if you live with young children or people with weakened immune systems.
  • Don’t allow cats to lick open wounds.
  • If you have a weakened immune system, adopt cats older than 1 year of age.
  • Avoid rough playing with pets because it may lead them to scratch and bite.

To control fleas and protect a cat’s health, the CDC suggests that owners take the following actions:

  • Keep the cat’s nails trimmed.
  • Apply a veterinarian-approved flea product (topical or oral medication) monthly.
  • Use a flea comb to inspect for flea dirt.
  • Vacuum frequently or contact pest control (if necessary) to treat areas in the home.
  • Schedule routine veterinary health checkups.
  • Keep cats indoors to decrease their contact with fleas and prevent them from fighting with potentially infected animals.

Last Reviewed: August 28, 2018