Cat Scratch Fever

What is 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 (papules) and a fever. B. henselae can infect you if a cat bites or scratches you or licks an open wound you have.

How common is cat scratch fever?

Cat scratch disease is relatively uncommon, with only about 12,000 people diagnosed every year in the U.S.

How serious is cat scratch fever?

Cat scratch disease rarely causes serious illness and usually goes away on its own. Complications from cat scratch disease hospitalize about 500 people each year in the U.S.

Who’s most at risk for cat scratch disease?

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

What does cat scratch fever look like?

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

What are the symptoms of cat scratch fever?

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

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

What causes cat scratch disease?

Infection with B. henselae bacteria causes cat scratch disease. If a cat scratches or bites you or licks an open wound, you can get infected with B. henselae.

How does cat scratch fever spread?

Fleas spread B. henselae, the bacteria that causes cat scratch disease, to cats. Cats (especially kittens) can have a blood infection from the bacteria without symptoms for months. Cats can then spread it to humans when their saliva comes in contact with an open wound (like a scratch or bite).

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

How is cat scratch disease diagnosed?

To diagnose cat scratch disease, your healthcare provider will perform a physical exam where 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 cat scratch disease is diagnosed with this exam alone. Your provider may also

• Take a sample of your blood to test for B. henselae bacteria.
• In rare cases, take a sample of fluid from one of your lymph nodes to test for B. henselae bacteria.

How is cat scratch fever treated?

Since cat scratch disease usually goes away on its own, treatment is usually to help your symptoms in the meantime. Your healthcare provider might prescribe the antibiotic azithromycin to try to get rid of the bacteria. This is usually only if you have a compromised immune system or your symptoms haven’t gone away within a couple of months.

How do I manage the symptoms of cat scratch fever?

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

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

If you have a very large or painful lymph node, you can ask your healthcare provider about having it drained to get relief.

How can I prevent cat scratch fever?

If you’re around cats, there are a few simple things you can do to help prevent cat scratch disease:

• Try to avoid cat bites or scratches.
• Wash your hands after playing with, picking up or petting cats or kittens.
• Keep your cats indoors to help reduce the risk of flea bites.
• Don’t pet or pick up stray cats or kittens.
• Don’t let cats lick scratches or wounds.
• Ask your veterinarian how to protect your cat from fleas.
• If you have a compromised immune system, adopt a cat over a year old rather than a kitten.

What’s the outlook for cat scratch fever?

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, cat scratch disease spreads to other organs, causing more serious illness.

How long does cat scratch fever last?

The main symptom of cat scratch disease, swollen lymph nodes, lasts anywhere from two to eight weeks. It usually resolves on its own.

What are the complications of CSD?

Cat scratch fever can become more serious if it spreads to other organs. Some complications include:

• Endocarditis. Inflammation of the lining around the heart that can cause muscle and joint aches, chest pain and night sweats. Endocarditis is life-threatening.
• Hepatosplenomegaly. A condition where your liver and spleen become swollen or enlarged. This can cause abdominal pain, nausea and vomiting.
• Parinaud's oculoglandular syndrome. A condition where a part of your eye (conjunctiva) gets inflamed and red and the lymph nodes near your ears are swollen.
• Neuroretinitis. Eye and optic nerve inflammation that can cause problems with your vision.
• Encephalopathy. Problems with brain function, including confusion, severe headaches and sometimes seizures.

How do I take care of myself?

If a cat’s scratched or bitten you, be sure to clean the wound and keep an eye on it. If it has signs of infection or if you experience symptoms of cat scratch disease, contact your healthcare provider.

When should I be concerned about a cat scratch?

You should be concerned about a cat scratch and visit your healthcare provider if you have:

• A scratch that’s not healing or is surrounded by a red area that gets bigger for more than 2 days.
• A fever that lasts for several days.
• Painful and swollen lymph nodes.
• Muscle, bone or joint pain.

When should I go to ER?

You should go to the ER if your wound isn’t healing and 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 questions should I ask my healthcare provider?

• Would antibiotics be appropriate for me?
• What symptoms should I look out for?
• When should I follow up with you?
• What should prompt me to call you or go to the ER?

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 cat scratch disease 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.

Do you need a tetanus shot after a cat scratch?

No, you don’t typically need a tetanus shot after a cat scratches you. But it’s still recommended that you get your initial series of tetanus shots and then get boosted every 10 years after that to be protected from more common ways to get tetanus.