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Overview

What Is Cat-Scratch Disease?

Cat-scratch disease is an infection caused by the bacterium Bartonella henselae. People most often get it when a cat scratch or bite breaks the skin, or when infected cat saliva reaches an open wound. Children and adolescents are affected more often because they may have closer contact with kittens and cats. Most cases are mild, treatable, and improve without lasting problems; it is also commonly called cat scratch fever or illness from a cat scratch.

Symptoms

Cat-Scratch Disease Symptoms

Cat-scratch disease symptoms often begin several days to a few weeks after a scratch or bite. The illness may be mild, but symptoms can vary depending on a person’s immune system and the part of the body affected.

  • A small bump or blister at the scratch or bite site (inoculation lesion)
  • Swollen lymph nodes near the injury (lymphadenopathy)
  • Fever
  • Fatigue
  • Headache
  • Reduced appetite

How It Spreads

How Cat-Scratch Disease Spreads

Infected cats can carry Bartonella henselae, often after acquiring the bacterium from fleas. A person may become infected when a cat scratch or bite breaks the skin, or when cat saliva reaches an open wound or the eye.

  • Kittens are more common sources than adult cats because they are more likely to carry the bacterium and scratch during play.
  • Stray cats may be more likely to carry Bartonella because of greater exposure to fleas and limited veterinary care.
  • Flea exposure increases the chance that a cat will carry and spread Bartonella.
  • Routine person-to-person spread is not typical; cat scratches, bites, and contaminated saliva are the usual concerns.

IMPORTANT DISTINCTION

The cat may appear healthy

A cat does not need to look ill to carry Bartonella. Wash a cat scratch or bite promptly with soap and running water, even when the wound seems minor.

Risk Factors

Cat-Scratch Disease Risk Factors

  • Contact with kittens or stray cats increases exposure to cat scratches and Bartonella.
  • Living with or handling flea-infested cats can increase the chance of cat scratch infection.
  • A scratch or bite that breaks the skin creates a possible entry point for infection.
  • Contact with cat saliva on broken skin can transmit Bartonella.
  • Children and adolescents may have more frequent exposure through rough play or close contact with cats.
  • Living with a weakened immune system increases the risk of severe or unusual disease.

Complications

Cat-Scratch Disease Complications

Most otherwise healthy people recover from cat-scratch disease without lasting problems. Complications are uncommon but can occur, particularly in people with weakened immunity.

  • Lymph nodes may remain inflamed or enlarged for an extended period.
  • Eye involvement can cause redness, pain, vision changes, or inflammation around the eye.
  • Neurologic disease can cause confusion, seizures, severe headache, or other nervous-system symptoms.
  • Bone infection can cause persistent, localized bone pain or swelling.
  • Liver or spleen involvement can cause abdominal symptoms or organ inflammation.
  • Heart-valve infection is a rare but serious complication.

SEEK PROMPT CARE

Unusual symptoms need medical assessment

Seek prompt medical care for vision changes, confusion, weakness, severe or persistent fever, or other unusual symptoms. People with significant immune suppression should contact a clinician early if symptoms develop.

Diagnosis

How Cat-Scratch Disease Is Diagnosed

Clinicians ask about contact with a cat or kitten, scratches, bites, flea exposure, the timing of symptoms, and immune status. They examine the skin lesion and nearby swollen lymph nodes, while considering other causes of fever, rash, or enlarged lymph nodes.

When testing may be needed

Blood testing for Bartonella antibodies or other Bartonella tests may be considered when illness is atypical, severe, persistent, or occurs in someone with weakened immunity. Clinicians may also order imaging or specialist tests if eye, neurologic, bone, liver, spleen, or heart complications are suspected.

Treatment & Management

Cat-Scratch Disease Treatment

Many mild cases improve with rest, fluids, and pain or fever relief recommended by a clinician. Some patients need antibiotics, depending on the severity of illness, complications, or immune status.

When antibiotics may be prescribed

Clinicians may prescribe antibiotics for persistent or severe disease, complications, or people with weakened immunity. Azithromycin is one example of a medicine that may be used in selected cases, but it should be taken only under medical direction.

  • Clean a cat scratch or bite promptly with soap and running water.
  • Do not apply prescription or over-the-counter antibiotic ointment unless a healthcare professional advises it.
  • Take any prescribed medicine exactly as directed and complete the plan recommended by your clinician.
  • Arrange follow-up if symptoms persist, worsen, or new symptoms develop.

MEDICATION SAFETY

Use antibiotics only when prescribed

Do not start leftover antibiotics or assume every cat scratch needs an antibiotic. Treatment depends on the wound, symptoms, complications, and your overall health.

Prevention

How to Prevent Cat-Scratch Disease

  • Wash your hands after handling cats, especially before eating or touching your eyes.
  • Clean cat scratches and bites promptly with soap and running water.
  • Avoid rough play that could lead to scratching or biting.
  • Keep cats indoors when appropriate to reduce contact with fleas and stray animals.
  • Use veterinary-recommended flea control for cats and the home.
  • Do not allow cats to lick open wounds, healing scratches, or other broken skin.

Outlook and Prognosis

Outlook for Cat-Scratch Disease

Most otherwise healthy people recover fully from cat-scratch disease. Swollen lymph nodes and fatigue can last for several weeks or longer, even after other symptoms improve.

  • Immune status influences the likelihood of a prolonged or more serious illness.
  • Organ involvement can make recovery more complex and may require closer monitoring.
  • Symptoms that persist or worsen may signal the need for additional evaluation.
  • Response to treatment helps clinicians assess recovery and decide whether follow-up is needed.

When Should You See a Doctor

When Should You See a Doctor?

GET MEDICAL CARE PROMPTLY

Some wounds need immediate evaluation

Seek urgent care for a deep puncture, uncontrolled bleeding, rapidly spreading redness or swelling, severe pain, or a bite from an unknown or potentially unvaccinated animal.

  • Fever develops after a cat scratch or bite.
  • Swollen lymph nodes persist, enlarge, or become more painful.
  • Pus, increasing redness, warmth, or swelling develops around the wound.
  • Eye symptoms such as pain, redness, or vision changes occur.
  • Neurologic symptoms such as confusion, weakness, or severe headache develop.
  • You have a weakened immune system and develop symptoms after cat exposure.

Tell the clinician about the cat exposure, when the wound occurred, possible flea exposure, any vaccination concerns, and any immune-suppressing condition or medicine. This information can help guide evaluation for an infected cat scratch or cat bite infection.

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