Cat Scratch Disease: Risks, Symptoms and Prevention

Most cat scratches are nothing more than a sting and a red mark. Just occasionally, though, a scratch or bite can pass on a bacterial infection called cat scratch disease. It is rarely serious in healthy adults, but it is worth understanding what it is, who needs to be careful, and the simple things that stop it happening in the first place.

I've kept cats for the best part of twenty years, and I've been caught by more overexcited kittens than I can count. The information here draws on UK veterinary and NHS guidance so you can tell the difference between a scratch that just needs a wash and one worth mentioning to your GP.

What cat scratch disease actually is

Cat scratch disease (CSD) is an infection caused by a bacterium called *Bartonella henselae*. People pick it up when a scratch, bite or lick over broken skin is contaminated with the bacteria. It's sometimes called cat scratch fever, though a fever isn't always part of it.

Here's the part that surprises most owners: the cat itself is usually perfectly healthy. Cats carry *Bartonella* in their bloodstream without showing any signs at all, and the bacteria mostly arrive on their claws and coat via flea dirt (dried flea faeces). So this isn't really a disease your cat "has" and passes on deliberately. It's a flea-borne bug that hitches a ride on an otherwise well cat.

Kittens and younger cats are more likely to be carrying it than older cats, partly because they're more prone to fleas and partly because they play rough. Feral and outdoor cats with heavier flea burdens carry higher rates too.

How common is it in UK cats

Carriage in the UK cat population is genuinely high. A veterinary review reports a *Bartonella henselae* prevalence of around 40.6% in domestic cats, with a lower figure of about 15.3% recorded in Scotland. A separate UK study that tested fleas taken from cats and dogs found *Bartonella* in 11.3% of flea samples, with most positive results coming from central and southern England.

Two things are worth taking from those numbers. First, a large share of ordinary pet cats carry the bacteria, so the exposure is common. Second — and this is the reassuring bit — actual cases of illness in people are far, far rarer than those carriage rates suggest. Being scratched by a cat that carries *Bartonella* very rarely leads to disease, especially in healthy adults.

Symptoms in people

Symptoms usually begin 3 to 14 days after the scratch or bite. The typical pattern runs like this:

• A small bump or blister at the site of the scratch, often appearing before anything else. It may look like a little raised spot and can be mistaken for an insect bite.
• Swollen, tender lymph nodes near the scratch — commonly in the armpit, neck or groin, depending on where you were caught. This is the most characteristic sign and can last for weeks.
• A mild fever, tiredness, headache, aching muscles and a reduced appetite in some people. Many never develop a fever at all.

In most healthy people the infection is mild and self-limiting. The swollen glands settle on their own, usually over several weeks and occasionally a couple of months. It's uncomfortable and a bit alarming, but it's not usually dangerous.

The rarer complications

A small number of people develop less usual forms. These include an eye version (Parinaud's oculoglandular syndrome) where a swollen gland appears in front of the ear alongside a red, irritated eye, and even rarer effects on the eye's retina, heart valves or nervous system. These are uncommon and much more likely in people with weakened immune systems. They need proper medical assessment rather than home management.

Who is most at risk

For most people, cat scratch disease is a minor nuisance at worst. The people who need to take it more seriously are:

• Anyone with a weakened immune system — for example people having chemotherapy, on immunosuppressant medication, or living with HIV. In this group *Bartonella* can cause more serious illness.
• Young children, who tend to play closely with cats and get scratched more often.
• Pregnant women, who understandably want to be cautious (though CSD is not among the well-known pregnancy risks the way toxoplasmosis is).

If you fall into one of these groups, it's sensible to be extra careful about flea control and to mention any persistent swollen glands to your doctor.

What to do if a scratch or bite breaks the skin

Good wound care straight away is your best defence, and it's the same sensible routine for any animal scratch or bite. NHS guidance for animal bites and scratches is clear and easy to follow:

1. Wash the wound with warm water and soap as soon as you can. 2. For a bite or deeper wound, gently encourage it to bleed a little by squeezing, unless it's already bleeding freely. 3. Pat it dry and cover with a clean, sterile dressing. 4. Watch it over the next few days for spreading redness, heat, swelling, pus or a bad smell.

Contact NHS 111 or your GP if the wound looks infected, if it's deep, if it's on your hand, foot, face or head, or if you develop swollen glands and feel unwell in the days afterwards. Tell them a cat scratched or bit you — it's a useful clue that points a clinician towards the right diagnosis, and it's easily missed if you don't mention it. Deep cat bites in particular can seal over and trap bacteria, so those are always worth getting checked.

A quick word of reassurance: the vast majority of cat scratches need nothing more than a rinse under the tap. This routine matters most for deeper bites, scratches that break the skin properly, and anyone in the higher-risk groups above.

How to prevent cat scratch disease

Because the bacteria travel on fleas, prevention comes down to two habits: keep fleas off your cat, and avoid getting scratched in the first place.

1. Stay on top of flea control

This is the single most effective step. Fleas are the vehicle, so a well-controlled cat is far less likely to be carrying *Bartonella* on its claws. UK veterinary advice (PDSA) is worth following closely:

• Treat your cat year-round with a suitable, licensed flea product on the schedule your vet recommends, rather than only when you spot a flea.
• Remember that around 95% of a flea problem lives in your home, not on the cat — carpets, bedding and soft furnishings. Vacuum regularly and wash pet bedding at 60°C.
• Never use a dog flea product on a cat. Many contain permethrin, which is extremely poisonous to cats and can be fatal. This is one of the most common and most avoidable causes of flea-treatment poisoning seen by UK vets.
• Prescription and pharmacy (NFA-VPS) treatments from your vet are generally more reliable than supermarket products.

If you're not sure how at-risk your household is, our parasite risk assessment tool can help you sense-check your flea routine.

2. Cut down on scratches and bites

Every scratch avoided is one less chance for the bacteria to get in.

• Don't encourage rough play, especially with kittens. Using your hands as toys teaches a cat to bite and scratch skin. Use wand toys and throw toys instead.
• Give your cat somewhere legitimate to scratch. A cat with a good scratching setup is calmer, less frustrated and less likely to lash out. If yours ignores its post, our guide on why your cat won't use the scratching post walks through the usual reasons. For enthusiastic, heavy scratchers, the advice on the best scratching post for aggressive scratchers is a good starting point.
• Keep claws trimmed if your cat tolerates it, or ask your vet or a groomer to do it. Blunter claws mean shallower scratches.
• Don't let your cat lick open wounds, cuts or grazes, and wash your hands after handling a new cat or kitten.
• Keep any scratch or bite clean using the wound-care steps above.

Common myths, cleared up

"An indoor cat can't give me cat scratch disease." Less likely, but not impossible — fleas get carried indoors on clothing, other pets and second-hand furniture, so indoor cats still need flea cover.

"My cat looks perfectly healthy, so it can't be carrying anything." Carrier cats almost always look completely well. Health status tells you nothing about carriage.

"I need to get my cat tested or treated." Routine testing or antibiotic treatment of healthy cats isn't recommended. The practical answer is flea control, not treating the cat for *Bartonella*.

"Declawing would solve it." Declawing is illegal in the UK and is not a solution. Trimming, scratching posts and flea control are the humane and effective route.

Cat scratch disease at a glance

| Question | Short answer | |---|---| | What causes it? | The bacterium *Bartonella henselae*, carried by fleas | | How do people catch it? | A scratch, bite or lick over broken skin contaminated with flea dirt | | When do symptoms appear? | Usually 3–14 days later | | Main signs | Bump at the scratch, swollen lymph nodes, sometimes mild fever | | Does it need antibiotics? | Not usually in healthy people; it self-resolves. Antibiotics for severe cases or weakened immunity | | Who's most at risk? | Immunocompromised people, young children | | Best prevention | Year-round flea control and prompt wound washing |

When to see a doctor

See your GP or call NHS 111 if, in the days or couple of weeks after a cat scratch or bite, you notice:

• Swollen, painful glands that don't settle
• A fever, marked tiredness or feeling generally unwell
• Spreading redness, swelling or pus around the wound
• Eye redness or vision changes
• Any concerning symptoms and you have a weakened immune system

Mention the cat scratch. It's the detail that most helps a clinician join the dots.

The bottom line

Cat scratch disease is real, but for most cat owners it's a low, manageable risk rather than a reason to worry about your cat. Keep fleas under control all year, give your cat proper outlets for scratching so you get caught less often, and wash any scratch or bite that breaks the skin. Do those three things and you've dealt with almost all of the risk — while your cat carries on being a healthy, happy part of the household.

Sources

• NHS – Animal and human bites
• Great Ormond Street Hospital – Bartonella (cat scratch fever)
• Vet Times – Bartonellosis in cats: update on management and treatment
• Abbott et al. – Pathogens in fleas collected from cats and dogs in the UK (Parasites & Vectors)
• Laycock, Day & Birtles – Prevalence of Bartonella henselae in cats in the UK (Veterinary Record, PubMed record)
• PDSA – Fleas on cats