
Cat scratch disease, also known as bartonellosis, is a bacterial infection caused by Bartonella henselae. It's usually transmitted through scratches or bites from an infected cat.
Symptoms of cat scratch disease can be mild and may include swollen lymph nodes, fever, headache, and fatigue. In some cases, the infection can cause more severe symptoms like swollen glands, eye inflammation, and even neurological problems.
Antibiotics are the primary treatment for cat scratch disease, and they're usually effective in reducing symptoms and preventing long-term complications. In severe cases, hospitalization may be necessary to manage symptoms and prevent further complications.
Preventing cat scratch disease is easier than treating it, and it starts with proper cat care. Keeping your cat's nails trimmed can reduce the risk of scratches, and washing your hands thoroughly after handling cats or their litter can also help prevent infection.
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What Is Cat Scratch Disease?
Cat scratch disease is a common issue many cat owners face. It's a disease in cats caused by the bacterium Bartonella henselae, spread through flea bites and cat scratches.
The bacteria are usually transmitted when fleas bite infected cats and then shed them in their droppings, which are found on the cat's fur.
Cat scratch disease can affect cats of any age, but it's most common in kittens, adult community cats, and those with weakened immune systems.
Most cats with cat scratch fever do not have symptoms, but if they do develop, it's essential to bring them to a veterinarian promptly for treatment.
Most cats with healthy immune systems are generally able to fight the infection themselves, so treatment is often not necessary.
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Causes and Diagnosis
Cat scratch disease is caused by bacteria that cats carry in their saliva, which they likely get from fleas. They can spread it to their paws or fur when they lick themselves.
You can get cat scratch disease from a cat biting, scratching, or licking you, or even if you rub your eyes after petting a cat that has the bacteria on its fur. Many people who get cat scratch disease don't remember being scratched or bitten by a cat.
Fleas can also spread the bacteria to humans, although this hasn't been proven. Cats, especially kittens, can have a blood infection from the bacteria without symptoms for months.
To diagnose cat scratch disease, your healthcare provider will perform a physical exam, looking at your scratch or wound, your skin for a rash or bumps, and feeling your lymph nodes. They may also take a sample of your blood to test for signs of a B. henselae infection.
Here's a summary of the diagnostic tests:
- Blood work to check for signs of infection, such as increased white blood cells or liver enzymes
- Bacterial culture to identify the type of bacterium causing the infection
- Lymph node aspirate to collect a sample from a swollen lymph node
How Veterinarians Diagnose
When diagnosing cat scratch fever in cats, veterinarians consider the cat's symptoms, vaccination history, and exposure to other cats. They may perform a physical examination to check for signs of infection.
Veterinarians can test for cat scratch fever using several methods, including blood work, bacterial culture, and lymph node aspirate. Blood work can check for signs of infection, such as increased white blood cells or liver enzymes. A bacterial culture can identify the type of bacterium causing the infection, but it's not routinely recommended due to the difficulty in culturing the Bartonella species.
A lymph node aspirate involves using a small needle to collect a sample from a swollen lymph node. This test can help confirm the diagnosis of cat scratch fever.
In some cases, veterinarians may be able to diagnose cat scratch fever without testing, but they may order a blood test to confirm the presence of Bartonella henselae bacteria.
What Causes Disease?
Cat scratch disease is caused by a type of bacteria that cats carry in their saliva. This bacteria, B. henselae, is likely picked up from fleas that infest the cat's fur.
Cats can spread the bacteria to their paws or fur when they lick themselves, making them a potential source of infection.
Fleas can also directly infect humans with B. henselae, although this hasn't been proven conclusively.
Cats, especially kittens, can have a blood infection from the bacteria without showing any symptoms for months. This means they can be carriers of the disease without anyone even realizing it.
You can get cat scratch disease from a cat biting, scratching, or licking you, and even just rubbing your eyes after petting a cat that has the bacteria on its fur.
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Symptoms and Complications
Symptoms of cat scratch disease can start as early as three to 10 days after a cat scratch or wound, and they can be quite varied. Bumps under your skin (papules) or a rash, swollen and painful lymph nodes, fever, muscle, bone or joint aches, loss of appetite or weight loss, and fatigue are all possible symptoms.
In most cases, symptoms start about 3-10 days after contact with an infected cat. A red bump, sore, or blister at the site of the scratch or bite is a common symptom, and it can last anywhere from one to three weeks or even persist for months.
You may also experience a low-grade fever, headache, fatigue, or poor appetite. The swollen lymph nodes usually develop within one to three weeks after you're scratched or bitten and appear near the area where you were infected.
Here are some possible complications of cat scratch disease:
- Neuroretinitis: a rare condition that causes inflammation of your optic nerve and the area of the retina around your optic nerve.
- Papillitis: another rare condition caused by inflammation and deterioration of your optic disk.
- Optic neuritis: inflammation and deterioration of the myelin sheath (fatty insulation) around your optic nerve.
- Parinaud's oculoglandular syndrome: swelling in the lining of your eye caused by an infection.
Symptoms of
Symptoms of cat scratch disease can start as early as three to 10 days after a cat scratch or wound. They can be quite varied, but often include bumps under your skin or a rash.

A red bump, sore, or blister may develop where a cat has bitten or scratched you. This could happen 3 to 10 days after the bite or scratch, and the sore or blister may take a long time to heal.
You may experience a low-grade fever, which is usually under 102 F. Headache, fatigue, and poor appetite are also common symptoms.
The swollen lymph nodes usually develop within one to three weeks after you're scratched or bitten and appear near the area where you were infected. For instance, if an infected cat bites your arm, the glands in your armpit or near your elbow may swell and become tender.
You may also experience bone or joint pain, abdominal pain without fever, vomiting, or diarrhea, or excessive tiredness for more than 2 or 3 weeks.
Here are some common symptoms to look out for:
- A red bump, sore, or blister at the site of the scratch or bite
- A low-grade fever (under 102 F)
- Headache
- Fatigue (feeling very tired)
- Poor appetite
- One or more swollen glands (lymph nodes)
- Bone or joint pain, abdominal pain without fever, vomiting, or diarrhea, or excessive tiredness for more than 2 or 3 weeks
Complications
Complications of Cat Scratch Fever can be serious and potentially long-lasting. The good news is that most people recover from the infection itself, but some may experience complications.

Some of these complications are rare, but they're still worth knowing about. Neuroretinitis, for example, can cause central vision loss in one eye, and it's often caused by the same bacteria that causes cat scratch fever.
Papillitis is another rare condition that can cause vision loss and color perception problems. In some cases, people may lose their sight within a few hours of experiencing symptoms. This is a serious warning sign that requires immediate medical attention.
Optic neuritis can cause eye pain, blurred vision, and reduced color perception. It's a sign that the myelin sheath around the optic nerve is deteriorating.
Parinaud's oculoglandular syndrome is a swelling of the eye lining that can cause red, irritated eyes and eye pain. It's often accompanied by conjunctival nodules on the eyelid or whites of the eye.
If you're young or have a weakened immune system, you're more likely to develop complications. This is why it's essential to take precautions if you're around cats or have a compromised immune system.
Here are some groups that are more likely to develop complications:
- Children under 5 years old
- People with weakened immune systems, such as those with cancer, diabetes, or HIV
Treatment and Management
Most people with cat scratch disease can recover on their own, but treatment can help ease symptoms.
Your healthcare provider might prescribe an antibiotic if you have a compromised immune system, complications, or long-lasting symptoms.
Antibiotics are rarely used for cat scratch disease, especially in children, but may be helpful for those with dissemination to the liver, spleen, eye, or central nervous system.
A single investigator found that antibiotics were rarely used in patients with lymphadenopathy believed to have CSD.
In some cases, antibiotics like azithromycin (Zithromax) may be prescribed for mild to moderate disease.
For cats with weakened immune systems or severe symptoms, treatment may be necessary, consisting of antibiotics for four to six weeks.
Common antibiotics used in cats include doxycycline and enrofloxacin.
Antibiotic treatment generally eliminates the bacterium, but cats can become re-infected if fleas are not properly addressed.
During recovery and in the initial post-treatment period, it's essential to prevent re-infection in cats by administering flea preventative and avoiding close contact with infected cats.
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If you have disseminated disease affecting your organs, a weakened immune system, or symptoms that haven’t gone away in two months, your doctor will likely prescribe antibiotics, usually azithromycin (Zithromax).
You may need to take antibiotics for several months to clear the infection, and it's crucial to follow your doctor's instructions and take the medication exactly as prescribed.
Prevention and Accommodation
Getting cat scratch disease can be a real bummer, but the good news is that it's preventable. To reduce your risk of infection, it's essential to keep your cats indoors to help prevent flea bites.
If you have a cat that's prone to fleas, talk to your veterinarian about other ways to protect your cat from these pesky parasites. Washing your hands after playing with, picking up, or petting cats or kittens is also crucial.
Don't pet or pick up stray cats or kittens, as they may be more likely to have fleas. If you do get scratched or bitten by a cat, be sure to clean the wound and keep an eye on it.
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Here are some additional tips to reduce your risk of infection:
- 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.
- 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.
- Call your provider if you develop symptoms of CSD.
When to See a Healthcare Provider
If you're experiencing symptoms of cat scratch disease, it's essential to know when to seek medical attention. Visit your healthcare provider if you have a scratch or wound that's not healing.
You should also see a healthcare provider if you notice a scratch or wound surrounded by a red or discolored area that gets bigger for more than two days. This could be a sign of infection.
A fever that lasts for several days is another reason to visit your healthcare provider. This could be a sign of a more serious underlying condition.
Painful and swollen lymph nodes are also a cause for concern. These symptoms can indicate that the infection has spread to your lymphatic system.
Here are some specific symptoms that require a visit to your healthcare provider:
- 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
Frequently Asked Questions
What is the first line treatment for cat-scratch disease?
Antibiotics like azithromycin are often prescribed as the first line treatment for cat-scratch disease, but in mild cases, medical treatment may not be necessary
What are the long term effects of cat-scratch disease?
Most people recover from cat-scratch disease with no long-term health consequences. However, rare cases can lead to serious infections of the brain, eyes, and heart.
What is the drug of choice for Bartonella?
The drug of choice for treating Bartonella is azithromycin, which has been shown to be effective in resolving symptoms. However, other cost-effective options like erythromycin or doxycycline may also be considered.
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