Cat Scratch Fever: What It Is, How It Spreads, and How It's Treated
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 17, 2026
Quick answer
Cat scratch fever is an uncommon bacterial infection caused by B. henselae, spread to people by a cat scratch, bite or lick on an open wound. It is most common in kids under 15. Symptoms include bumps near the scratch, swollen painful lymph nodes, fever and fatigue, starting 3 to 10 days later. It usually goes away on its own. [1]
What the research says
According to PubMed:
Cat scratch disease is most common in young children and in the South. A review of U.S. insurance claims from 2005–2013 found the highest incidence in the South (6.4 cases per 100,000) and in children aged 5–9 years (9.4 per 100,000), with an estimated 12,000 outpatient diagnoses and 500 hospitalizations each year; flea control for cats was highlighted as a key prevention step. (Nelson et al., Emerg Infect Dis, 2016). [7]
Most cases show up as one swollen lymph node, though some children have deeper disease. In 150 children at an Argentine pediatric hospital, 84.7% came in with a solitary swollen lymph node, 44% received antibiotics (mainly for lymph nodes that stayed swollen), and 14% were hospitalized. (Deregibus et al., Arch Argent Pediatr, 2023). [5]
Fever with a high C-reactive protein can flag spread beyond the lymph nodes. Among 197 children with cat scratch disease at a Buenos Aires pediatric hospital, 34.5% had systemic involvement (most often splenic or liver abscesses). Fever was more common in those children (79.4% vs. 50.3%), and most patients recovered fully with no deaths reported. (Martínez Lindado et al., Pediatr Infect Dis J, 2025). [6]
Study details are from PubMed abstracts.
What Is Cat Scratch Fever?
Cat scratch fever is an illness caused by the bacteria Bartonella henselae (B. henselae). You may also hear it called cat scratch disease, or CSD for short. The infection causes swollen lymph nodes, bumps on your skin, and a fever. [1]
B. henselae can infect you if a cat bites or scratches you, or if a cat licks an open wound you already have. Cats themselves pick up the bacteria from flea bites, and kittens — especially young kittens — can carry the bacteria in their blood for months without showing any symptoms. [1]
The most common symptoms are a rash or bumps under your skin and swollen, painful lymph nodes. The lymph nodes can stay swollen for several weeks, but they usually improve on their own. [1]
What Does Cat Scratch Fever Look Like?
Cat scratch disease has two telltale signs: swollen lymph nodes and bumps under your skin (called papules). The bumps can look like a rash or more like small nodules, and they usually appear near the infected wound. [1]
What Are the Symptoms of Cat Scratch Fever?
Symptoms of cat scratch disease typically start three to 10 days after a cat scratch or wound. The most common symptoms are bumps or a rash near the scratch and swollen, painful lymph nodes. [1]
Symptom | What you might notice |
Bumps under the skin (papules) or a rash | Small nodules or a rash, usually near the infected wound |
Swollen, painful lymph nodes | Lumps under the skin that stay swollen for weeks |
Fever | An elevated body temperature |
Muscle, bone, or joint aches | Achy feeling in muscles, bones, or joints |
Loss of appetite or weight loss | Not wanting to eat, or losing weight |
Fatigue | Feeling unusually tired |
The lymph nodes can stay swollen anywhere from two to eight weeks, but they usually get better on their own. [1]
What Causes Cat Scratch Fever?
B. henselae bacteria cause cat scratch disease, and fleas spread these bacteria to cats. Here is how the chain of infection works: [1]
Step | What happens |
1. Fleas bite cats | Fleas carry B. henselae and pass the bacteria to cats through bites |
2. Cats carry the bacteria | Cats — especially kittens — can have a blood infection without symptoms for months |
3. Cats spread it to people | A scratch, bite, or a lick on an open wound passes the bacteria to you |
It is possible that getting bitten directly by a flea could also give you cat scratch disease, but this has not been proven. [1]
Who Is at Risk for Cat Scratch Fever?
Anyone who is around cats is at risk for cat scratch disease. However, it is most common in kids under 15. [1]
People with HIV or a weakened immune system (being immunocompromised) face a higher risk of serious complications from the infection. [1]
What Are the Complications of Cat Scratch Fever?
Cat scratch fever usually stays mild, but it can become more serious if the bacteria spread to other organs. Possible complications include: [1]
Complication | What it involves |
Encephalopathy | Brain function issues |
Endocarditis | Inflammation of the heart |
Heart failure | The heart struggles to pump effectively |
Hepatosplenomegaly | Swelling of the liver and spleen |
Parinaud oculoglandular syndrome | Inflammation of the conjunctiva (the clear membrane of the eye) and nearby lymph nodes |
Neuroretinitis | Inflammation of the retina and optic nerve of the eye |
People with a weakened immune system can also develop two less common conditions: bacillary angiomatosis and bacillary peliosis. Bacillary angiomatosis causes extra blood vessels to form, creating masses or cysts on the organs and bones, and can cause large, raised bumps on the skin that may look darker than the surrounding skin or bright red, depending on skin tone. Bacillary peliosis causes blood-filled cysts on the liver. [1]
How Is Cat Scratch Fever Diagnosed?
To diagnose cat scratch disease, a healthcare provider starts with a physical exam. They will look at your scratch or wound (if you have one), check your skin for a rash or bumps, and feel your lymph nodes. [1]
Sometimes the exam alone is enough to make the diagnosis. Your provider may also take a blood sample 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. [1]
How Is Cat Scratch Fever Treated?
Since cat scratch disease usually goes away on its own, treatment often focuses on easing your symptoms in the meantime. A provider might prescribe an antibiotic to get rid of the bacteria — but this is usually reserved for people with a compromised immune system, complications, or long-lasting symptoms. [1]
If you have a very large or painful lymph node, your provider might drain it. [1]
How do I manage symptoms at home?
You can manage the symptoms of cat scratch disease at home by taking over-the-counter (OTC) pain medicines like ibuprofen (Advil) or naproxen (Aleve) for pain relief, and by applying a warm compress to painful lymph nodes. [1]
When Should I See My Healthcare Provider?
Contact your healthcare provider if you develop any of the following after a cat scratch or bite: [1]
Warning sign | Why it matters |
A scratch or wound that is not healing | May signal infection |
Red or discolored skin around a scratch that grows for more than two days | Suggests the infection is spreading |
Fever that lasts for several days | A sign the body is fighting infection |
Painful, swollen lymph nodes | A hallmark symptom of CSD |
Muscle, bone, or joint pain | Another possible symptom of the infection |
When Should I Go to the ER?
Cat scratch fever needs emergency care if symptoms suggest the infection has spread, such as high fever, confusion, severe headaches, seizures, chest pain or abdominal pain with vomiting. [1]
High fever
Confusion
Severe headaches
Seizures
Chest pain or shortness of breath
Abdominal pain with nausea or vomiting
How Long Does Cat Scratch Fever Last?
Swollen lymph nodes from cat scratch disease last anywhere from two to eight weeks. They usually improve on their own, and the full illness typically resolves over a few weeks or months. [1]
What's the Outlook?
Cat scratch disease is usually self-limiting — meaning 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 and causes serious illness. [1]
Can Cat Scratch Fever Be Prevented?
Yes, simple habits around cats go a long way toward preventing cat scratch fever. If you are around cats, try to avoid bites and scratches, and don't let cats lick wounds you have. Beyond that, several practical steps reduce your risk: [1]
Prevention step | How it helps |
Wash hands after playing with, picking up, or petting cats and kittens | Removes bacteria before it enters a wound or your eyes and mouth |
Keep cats indoors | Reduces their risk of flea bites that carry the bacteria |
Talk to your vet about flea protection | Helps protect your cat from the flea-bite route |
Avoid petting stray cats or kittens | Strays are more likely to carry the bacteria |
Clean any scratch or bite right away | Washing and watching the wound catches problems early |
If immunocompromised, adopt a cat over a year old rather than a kitten | Kittens are more likely to carry the bacteria |
Can you get cat scratch fever from an indoor cat?
Since cats pick up B. henselae from fleas, it is less likely you would catch CSD from an indoor cat that never goes outdoors. However, if your cat has had fleas or is newly adopted — especially a kitten — they could still carry the bacteria. [1]
What's the Bottom Line?
Cat scratch fever is an uncommon bacterial infection caused by B. henselae, passed to people when an infected cat scratches, bites, or licks an open wound. It starts three to ten days later with bumps or a rash near the scratch and swollen, painful lymph nodes, plus fever, aches, and fatigue. Most cases — especially in kids under 15, the group most often affected — clear up on their own within a few weeks without treatment. Washing hands after handling cats, keeping cats indoors, avoiding strays, and cleaning scratches promptly keep the risk low. And if a high fever, confusion, severe headaches, seizures, chest pain, or abdominal pain ever follow a cat scratch, that is a signal to seek emergency care. [1]
Ready to learn more? Visit Rinnit.com for trusted, easy-to-understand health guides like this one — including more pet-and-family health guides.
Frequently asked questions
What is cat scratch fever?
Cat scratch fever (also called cat scratch disease, or CSD) is an uncommon bacterial infection caused by Bartonella henselae (B. henselae). It causes swollen lymph nodes, bumps on the skin, and a fever, and it spreads from cats through a scratch, bite, or lick on an open wound. [1]
What causes cat scratch fever?
The bacteria Bartonella henselae cause it. Fleas spread the bacteria to cats, and cats — especially kittens — pass it to people when they scratch, bite, or lick an open wound. [1]
How do cats get the bacteria?
Cats get infected through flea bites. Kittens can carry the bacteria in their blood for months without showing any symptoms. [1]
How long after a cat scratch do symptoms appear?
Symptoms typically start three to 10 days after the cat scratch or wound. [1]
What does cat scratch fever look like?
Cat scratch fever has two telltale signs: bumps under the skin (papules) that can look like a rash or nodules, usually near the infected wound, and swollen, painful lymph nodes. [1]
What are the symptoms of cat scratch fever?
Bumps or a rash near the scratch, swollen and painful lymph nodes, fever, muscle, bone, or joint aches, loss of appetite or weight loss, and fatigue. [1]
How long does cat scratch fever last?
Swollen lymph nodes last two to eight weeks and usually improve on their own. The whole illness typically clears up within a few weeks or months. [1]
Who is most likely to get cat scratch fever?
Anyone around cats is at risk, but it is most common in kids under 15. [1]
Can I get cat scratch fever from an indoor cat?
It is less likely, because cats get the bacteria from fleas and indoor cats are less exposed. But a cat that has had fleas or is newly adopted — especially a kitten — could still carry the bacteria. [1]
Is cat scratch fever contagious from person to person?
The illness spreads from cats to people, typically through a scratch, bite, or lick on an open wound. It is not described as spreading directly between people.
How is cat scratch fever diagnosed?
A provider performs a physical exam — looking at the wound, checking the skin for bumps or a rash, and feeling the lymph nodes. A blood test for B. henselae may be used, and in rare cases a fluid sample from a lymph node is tested. [1]
How is cat scratch fever treated?
Cat scratch fever usually goes away on its own. Treatment focuses on easing symptoms with over-the-counter pain medicine like ibuprofen or naproxen and warm compresses on swollen lymph nodes. Antibiotics are usually prescribed only for people with a weakened immune system, complications, or long-lasting symptoms. A very large or painful lymph node may be drained by a provider. [1]
When should I see a doctor for a cat scratch?
See a provider if a scratch or wound is not healing, if red or discolored skin around it grows for more than two days, if you have a fever lasting several days, or if you develop painful swollen lymph nodes or muscle, bone, or joint pain. [1]
When should I go to the ER?
Go to the emergency room if you develop signs the infection has spread: high fever, confusion, severe headaches, seizures, chest pain or shortness of breath, or abdominal pain with nausea or vomiting. [1]
Can cat scratch fever cause serious complications?
Cat scratch fever can. If the infection spreads to other organs, it may cause brain function issues (encephalopathy), heart inflammation (endocarditis), heart failure, liver and spleen swelling, eye inflammation (Parinaud oculoglandular syndrome or neuroretinitis), and — in people with weakened immune systems — bacillary angiomatosis or bacillary peliosis. [1]
What is bacillary angiomatosis?
A condition that can develop in people with weakened immune systems. It causes excess blood vessels to form, creating masses or cysts on the organs and bones, and can cause large, raised skin bumps that may be darker than the surrounding skin or bright red depending on skin tone. [1]
What is bacillary peliosis?
A condition that can develop in people with weakened immune systems. It causes blood-filled cysts on the liver. [1]
How can I prevent cat scratch fever?
Avoid cat bites and scratches, don't let cats lick your wounds, wash hands after handling cats, keep cats indoors to reduce flea exposure, don't pet stray cats or kittens, and clean any scratch or bite right away. People with weakened immune systems should consider adopting a cat over a year old instead of a kitten. [1]
Does cat scratch fever have long-term effects?
Usually not. The disease is typically self-limiting, meaning it goes away on its own without complications or long-term effects. In a small number of people, the infection spreads to other organs and causes serious illness. [1]
Related reading
This article is for general informational purposes only and does not constitute medical advice, diagnosis, or treatment. Always seek the guidance of your physician or other qualified health provider with any questions about a medical condition. Never disregard professional medical advice or delay seeking care because of something you have read here. If you think you may have a medical emergency, contact emergency services or your local emergency department immediately.
References
Cleveland Clinic. Cat Scratch Fever. Cleveland Clinic. Last updated August 11, 2025. https://my.clevelandclinic.org/health/diseases/23537-cat-scratch-fever
Centers for Disease Control and Prevention. About Cat Scratch Disease. Centers for Disease Control and Prevention. Last updated March 23, 2026. https://www.cdc.gov/bartonella/about/about-cat-scratch-disease.html
Bush LM, Vazquez-Pertejo MT. Cat-Scratch Disease. Merck Manual Professional Version. Last updated September 2026. https://www.merckmanuals.com/professional/infectious-diseases/gram-negative-bacilli/cat-scratch-disease
Bush LM, Vazquez-Pertejo MT. Bacillary Angiomatosis. Merck Manual Professional Version. Last updated June 2024. https://www.merckmanuals.com/professional/infectious-diseases/gram-negative-bacilli/bacillary-angiomatosis
Deregibus MI, Bagnara EI, Buchovsky A. Cat-scratch disease: experience in a tertiary care children's hospital. Arch Argent Pediatr. 2023;121(1):e202202592. PMID 36315437. https://doi.org/10.5546/aap.2022-02592.eng
Martínez Lindado MA, Praino ML, Caratozzolo A, et al. Cat scratch disease in pediatrics: who has systemic involvement? Pediatr Infect Dis J. 2025;44(1):18-23. PMID 39230263. https://doi.org/10.1097/INF.0000000000004536
Nelson CA, Saha S, Mead PS. Cat-scratch disease in the United States, 2005-2013. Emerg Infect Dis. 2016;22(10):1741-1746. PMID 27648778. https://doi.org/10.3201/eid2210.160115
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