Cat-Scratch Disease: What Owners Should Know

In this guide

Cat-scratch disease is a bacterial infection people can pick up after being scratched, bitten, or licked by a cat. Cats carry the responsible bacteria in their saliva, most likely picked up originally from fleas. It is not usually serious in otherwise healthy adults, but it can be more troublesome for young children or anyone with a weakened immune system, including people with cancer, diabetes, or HIV/AIDS.

Symptoms

A red bump, sore, or blister can appear where the skin was broken, typically three to ten days afterwards, and it may take a while to heal fully. Some people also develop a mild fever (below 102°F/38.9°C), headache, tiredness, or reduced appetite. The lymph nodes nearest the injury, for example under the arm if the scratch was on the arm, can become swollen and tender.

See a doctor if a scratch or bite is not healing, if redness keeps spreading for more than two days, if a fever persists for several days, if swollen lymph nodes last beyond two or three weeks, or if bone or joint pain, abdominal pain without other obvious cause, or persistent fatigue continue for more than two or three weeks.

Causes

The bacteria live in cat saliva, likely originally acquired from fleas, and can transfer to a cat's paws or fur through self-grooming. People can be infected via a scratch, bite, or lick, or even by rubbing their eyes after petting a cat with the bacteria on its coat. Many people who develop the disease do not even recall being scratched or bitten.

Diagnosis

A doctor will examine the wound, ask about symptoms, and check the lymph nodes for swelling and tenderness. A blood test may follow if the diagnosis is not obvious from the examination alone.

Prevention

• Wash your hands thoroughly after handling your cat.
• Play gently so the cat has no reason to scratch or bite.
• Avoid letting a cat lick you, especially near the mouth, nose, eyes or an open wound.
• Keep on top of flea control to reduce the chance of the bacteria being present at all.
• Do not tease or provoke a cat.
• Avoid petting stray or feral cats.

Young cats carry the bacteria more often than older ones, and households with kittens, particularly kittens with fleas, have higher infection rates. If you are choosing a new cat and this is a concern, an adult cat over a year old carries lower risk.

Treatment

Most cases clear up on their own. Over-the-counter pain relief such as ibuprofen or naproxen, along with warm compresses, can ease discomfort. A doctor may drain a particularly large or painful lymph node. If symptoms persist beyond a month or two, antibiotics may be prescribed, and in rare cases where infection spreads to the bones, liver or other organs, more intensive treatment is needed.

Cats themselves rarely become unwell from carrying the bacteria and usually need no treatment, though very occasionally it can cause heart inflammation that affects breathing; contact your vet if you are concerned.

If you are scratched or bitten

Wash the area with soap and water straightaway, then watch for signs of infection over the following two weeks. Most people manage any symptoms at home with pain relief or warm compresses, but call your doctor if anything concerning develops.

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