Cat scratch fever occurs when a person is bitten, scratched, or licked by a cat infected with the bacteria Bartonella henselae.
The infection doesn’t usually cause severe complications. However, it’s possible that it can in people with weak immune systems. Knowing the causes and symptoms can ensure a person receives swift treatment.
Cats can transmit several types of infections to humans. Some of these diseases can be severe. Carrying out routine care for a cat often reduces the risk of many of these diseases.
A person can get cat scratch fever if they are scratched or bitten by an infected cat. The B. henselae bacteria live in a cat’s saliva, and can also be passed to a person through an open area of skin.
People are most likely to experience cat scratch fever in the fall and winter when they’re inside and play with their cats. Kids are more likely than adults to have the condition. They can play with cats more roughly, making them more likely to be scratched.
Cat scratch fever doesn’t usually cause symptoms in the first few days after a person is exposed. During this time, the bacteria are multiplying in the body.
About 3 to 10 days after a person is scratched, they may notice a small bump or blister on the affected area. Doctors call this an inoculation lesion. These lesions are commonly seen on the:
A few weeks later, a person will usually see the lymph nodes near the lesion swollen or tender.
Lymph nodes are responsible for filtering bacteria and other particles as well as creating immune system cells. They usually feel like small, spongy, round or oval bumps.
If a person was bitten or scratched on the arm, the lymph nodes under the arm or near the elbow may be especially tender.
Sometimes, the lymph nodes swell as much as 2 inches across. They may be warm to the touch, pus-filled, or red in color. The lymph nodes may remain swollen for anywhere from 2 to 4 months after the initial infection.
Most people only have swollen lymph nodes as a symptom. Other symptoms associated with cat scratch fever include:
Cat scratch fever doesn’t usually cause severe symptoms. However, some people may develop a high fever that doesn’t seem to go away with time.
Some people can also experience infections in the bones, joints, liver, lungs, or spleen. According to the Centers for Disease Control and Prevention (CDC), the most severe symptoms usually occur in children ages 5 and under.
While cat scratch fever isn’t a condition that usually requires emergency care, there are always exceptions. A person should contact their doctor immediately if they experience the following symptoms:
Cat scratch fever can be hard to diagnose as the symptoms are similar to a lot of other conditions. A doctor will ask about a person’s medical history and any interactions a person may have had a cat.
A doctor will then conduct a physical examination, looking at the scratched area and any swollen lymph nodes. Examination and medical history are often enough to make a diagnosis.
The doctor may order additional tests to make sure another condition isn’t causing the symptoms. They could take a sample of blood and send it to a lab to determine what type of bacteria is growing.
Doctors can also order a blood test that specifically tests for cat scratch fever.
As most cases of cat scratch fever are mild, a doctor won’t always prescribe a treatment. If symptoms are moderate to severe, they may prescribe an antibiotic.
At-home treatments for the condition include bed rest and an over-the-counter pain reliever if the lymph nodes are painful or especially tender.
While children don’t have to stop playing, they should avoid hitting or interfering with the affected lymph nodes.
Once a person has had cat scratch fever once, they’re unlikely to get the disease again.
While cats can transmit cat scratch fever to people, people don’t usually pass it to others. If one family member is affected, others should practice caution around the family cat as the cat could infect them too.
An episode of cat scratch fever also doesn’t mean a family should necessarily get rid of their pet. However, they can practice the following preventive techniques:
According to the CDC, an estimated 40 percent of cats carry the B. henselae infection at some point in their lives. Most of the time, cats that carry the infection don’t show signs of illness.
Cats get the infection when they scratch and bite at fleas that infect them or fight with cats that are infected. If a cat has fleas or visible scratches, these could be signs a person should practice caution when handling their cat. Once a cat is infected, it can carry the disease for several months.
In rare cases, cat scratch disease can cause severe symptoms in cats, including inflammation of the heart. Cats may have difficulty breathing due to this. Upon examination, a vet may also identify inflammation in the eyes, mouth, or urinary system.
A vet can inspect a cat for fleas and make recommendations regarding flea prevention and avoiding scratches and bites.
While there is a blood and fluid test available for the Bartonella bacteria, doctors don’t usually recommend it for cats that don’t have symptoms. The bacteria are very common, and the test can be unreliable.
Cats aren’t usually treated with antibiotics unless they have noticeable symptoms.
Taking steps to reduce fleas in a cat can reduce the likelihood of cat scratch fever. People can care for their cats by doing the following:
Vaccines aren’t currently available against cat scratch disease bacteria.
Cats can carry and spread additional diseases besides cat scratch fever. These diseases include: