Cat scratch fever, also known as cat scratch disease, clears up on its own in 90% to 95% of cases without antibiotics. Swollen lymph nodes typically last two to eight weeks before resolving. For most people, the treatment plan is simple: manage symptoms at home while your immune system does the work. Antibiotics are reserved for severe or lingering cases, and for people with weakened immune systems who face a higher risk of complications.
Home Care for Mild Cases
Since the infection is self-limited in the vast majority of cases, supportive care is the first-line approach. That means treating the symptoms rather than the bacteria directly. Over-the-counter pain relievers like ibuprofen or acetaminophen can handle both the discomfort from swollen lymph nodes and any low-grade fever. Applying a warm compress to the swollen area several times a day can also ease tenderness and help with drainage.
The scratch or bite wound itself should be washed thoroughly with soap and water as soon as it happens. Keep the area clean as it heals. Most people develop a small bump or blister at the wound site within 3 to 10 days, followed by swollen lymph nodes near the scratch a week or two later. These swollen nodes are the hallmark of the disease and can get quite tender, but they don’t usually need medical intervention.
When Antibiotics Are Needed
Antibiotics are typically prescribed when the infection is severe, when lymph nodes become very large or filled with pus, or when the patient has a weakened immune system (from HIV, chemotherapy, or organ transplant medications, for example). The most commonly used antibiotic is azithromycin, taken as a five-day course. Adults take a higher dose on the first day, then a lower dose for the remaining four days. Children receive a weight-based dose following the same pattern.
Azithromycin is the preferred choice because it has the strongest clinical evidence for reducing lymph node size faster than no treatment. Other antibiotics that have shown some effectiveness in individual reports include doxycycline, rifampin, and a common sulfa-based antibiotic. However, most studies have found limited benefit from antibiotics in uncomplicated cases, which is why they’re not routinely prescribed for typical infections in otherwise healthy people.
Draining Swollen Lymph Nodes
In some cases, a lymph node becomes so swollen and painful that it fills with pus and needs to be drained. This is called a suppurative lymph node. A doctor can relieve the pressure with needle aspiration, which involves inserting a needle to draw out the fluid. This often provides immediate pain relief. Surgical removal of the node is rarely necessary but may be considered if aspiration doesn’t resolve the problem.
Treating Complications
Roughly 5% to 10% of cat scratch fever cases develop complications beyond the typical swollen lymph nodes. The most significant involve the eyes, liver, spleen, or nervous system.
Eye involvement, specifically a condition called neuroretinitis, causes sudden blurred vision or vision loss in one eye. This happens when the bacteria travel to the retina and optic nerve. Treatment involves a longer course of antibiotics, often azithromycin or doxycycline for up to six weeks rather than the standard five days. When vision is significantly impaired at the time of diagnosis, doctors may add a short course of oral steroids to reduce inflammation, tapering the dose over about a month. In documented cases, this combination of antibiotics and steroids has led to meaningful recovery of vision.
For immunocompromised patients, the bacteria can cause more serious conditions like bacillary angiomatosis (abnormal blood vessel growths in the skin) or peliosis hepatis (blood-filled cavities in the liver). These require combination antibiotic therapy, typically lasting several months, and close medical monitoring.
How Diagnosis Works
If your doctor suspects cat scratch fever, they’ll likely order a blood test that checks for antibodies against the bacteria. The test measures two types of antibodies: IgM, which indicates a current infection, and IgG, which can reflect either a current or past infection. A positive IgM result above a certain threshold is strong evidence of active disease. If IgG levels rise between two blood draws taken a few weeks apart, that also confirms an active infection.
Diagnosis often relies on the combination of blood test results, a history of cat exposure, and the presence of swollen lymph nodes near a scratch or bite wound. In some cases, a doctor may biopsy the swollen lymph node to rule out other causes like lymphoma, especially if the swelling persists for months.
What Recovery Looks Like
Most people feel better within a few weeks, but the swollen lymph nodes can linger. Two to eight weeks is the typical range, though some nodes take several months to fully shrink. This slow resolution is normal and doesn’t mean the infection is worsening or that antibiotics are needed. Fatigue and general malaise can also persist for a few weeks after the acute phase.
Reinfection is uncommon. Most people develop lasting immunity after a single episode of cat scratch disease.
Preventing Cat Scratch Fever
The bacteria responsible for cat scratch disease, Bartonella henselae, spreads primarily through flea feces. When a cat scratches or bites you, flea dirt (flea droppings containing the bacteria) on the cat’s claws or teeth gets pushed into the wound. Kittens under one year old are the most likely carriers, and they’re more prone to scratching during play.
The most effective prevention strategies target the flea-to-cat-to-human chain:
- Use veterinarian-recommended flea prevention on your cats year-round. Never use permethrin-containing products on cats, as these are toxic to them.
- Wash scratches and bites immediately with soap and running water.
- Avoid rough play with cats, especially kittens, that could lead to scratches or bites.
- Keep cats indoors and away from strays to reduce flea exposure.
- Wash your hands after handling any cat, particularly before touching your face or any open wounds.
The CDC specifically notes that declawing cats is not recommended as a prevention strategy. People with weakened immune systems should consider adopting cats that are at least one year old, in good health, and free of fleas rather than bringing home kittens.