Cat Scratch Fever

Cat scratch fever (usually called cat scratch disease or CSD) is an illness caused by the bacteria Bartonella henselae (B. henselae). It causes swollen lymph nodes, bumps on your skin and a fever. B. henselae can infect you if a cat bites or scratches you or licks an open wound you have.

What does cat scratch fever look like?

Cat scratch disease has two telltale signs: swollen lymph nodes and bumps under your skin (papules). The bumps can look like a rash or more like nodules, and they’re usually near the infected wound.

Symptoms of cat scratch fever

Symptoms of cat scratch disease start three to 10 days after a cat scratch or wound. They include:

• Bumps under your skin (papules) or a rash
• Swollen, painful lymph nodes
• Fever
• Muscle, bone or joint aches
• Loss of appetite or weight loss
• Fatigue

CSD causes

B. henselae bacteria cause cat scratch disease. Fleas spread B. henselae to cats. Cats (especially kittens) can have a blood infection from the bacteria without symptoms for months. Cats can then spread the bacteria to humans when they scratch or bite you, or if they lick a wound you already have.

It’s possible that getting bitten directly by a flea could give you cat scratch disease, but this hasn’t been proven.

Risk factors

Anyone who’s around cats is at risk for cat scratch disease. But it’s most common in kids under 15. If you have HIV or a weakened immune system, you’re at higher risk for serious complications of cat scratch disease.

Complications

CSD can become more serious if it spreads to other organs. Complications include:

• Brain function issues (encephalopathy)
• Heart inflammation (endocarditis)
• Heart failure
• Liver and spleen swelling (hepatosplenomegaly)
• Inflammation of the conjunctiva of your eye and nearby lymph nodes (Parinaud oculoglandular syndrome)
• Inflammation of the retina and optic nerve of your eye (neuroretinitis)

If you have a weakened immune system, you might develop bacillary angiomatosis or bacillary peliosis. Bacillary angiomatosis causes excess blood vessels to form, creating masses or cysts on your organs and bones. You might get large, raised bumps on your skin. Depending on your skin tone, they might be darker than the surrounding skin or bright red. Bacillary peliosis causes blood-filled cysts on your liver.

How doctors diagnose CSD

To diagnose cat scratch disease, your healthcare provider will perform a physical exam. They’ll:

• Look at your scratch or wound (if you have one)
• Look at your skin for a rash or bumps
• Feel your lymph nodes

Sometimes, a provider diagnoses cat scratch disease just with this exam. Your provider may also take a sample of your blood to test for signs of a B. henselae infection. In rare cases, they might take a sample of fluid from one of your lymph nodes to test for infection.

How is cat scratch fever treated?

Since cat scratch disease usually goes away on its own, treatment often aims to help ease your symptoms in the meantime. Your healthcare provider might prescribe an antibiotic to get rid of the bacteria. This is usually only if you have a compromised immune system, complications or long-lasting symptoms.

If you have a very large or painful lymph node, your healthcare provider might drain it.

How do I manage the symptoms at home?

You can manage the symptoms of cat scratch disease at home by:

• Taking over-the-counter (OTC) medicines for pain relief, like ibuprofen (Advil^®) or naproxen (Aleve^®)
• Applying a warm compress to painful lymph nodes

How long does cat scratch fever last?

Swollen lymph nodes from cat scratch disease last anywhere from two to eight weeks. They usually get better on their own.

When should I see my healthcare provider?

Visit your healthcare provider if you have:

• A scratch or wound that’s not healing
• A scratch or wound surrounded by a red or discolored area that gets bigger for more than two days
• A fever that lasts for several days
• Painful and swollen lymph nodes
• Muscle, bone or joint pain

When should I go to the ER?

Go to the emergency room if you have symptoms of an infection that’s spread to other parts of your body, including:

• High fever
• Confusion
• Severe headaches
• Seizures
• Chest pain or shortness of breath
• Abdominal pain with nausea or vomiting

What can I expect if I have CSD?

Cat scratch disease is usually self-limiting — that means that it goes away on its own without causing complications or long-term effects. In a small number of people, the infection spreads to other organs, causing serious illness.

Can cat scratch fever be prevented?

If you’re around cats, try to avoid bites or scratches and don’t let them lick wounds you have. A few other things you can do to reduce your risk of infection include:

• Wash your hands after playing with, picking up or petting cats or kittens.
• Keep your cats indoors to help reduce their risk of flea bites. Talk to your veterinarian about other ways to protect your cat from fleas.
• Don’t pet or pick up stray cats or kittens.
• If you have a compromised immune system, adopt a cat over a year old rather than a kitten.
• If a cat’s scratched or bitten you, be sure to clean the wound and keep an eye on it. Call your provider if you develop symptoms of CSD.

Can you get cat scratch fever from an indoor cat?

Since cats get B. henselae infections from fleas, it’s less likely that you’d get CSD from an indoor cat who never goes outdoors. If your cat has had fleas or is newly adopted (especially a kitten), they could have a B. henselae infection.