What Causes Cat Scratches to Swell?
Cat scratches can lead to swelling for a few common reasons:
- Allergic reactions to cat saliva entering the wound – Some people are allergic to substances in cat saliva which can trigger swelling when introduced directly into a wound from a scratch (source).
- Bacterial infections from bacteria on the cat’s claws – Cats’ claws can harbor bacteria that get introduced into the scratch, causing an infection and inflammation. Common bacteria include Pasteurella, Staphylococcus, and Streptococcus (source).
- The body’s inflammatory response – Scratches, like any wound, trigger the body’s inflammatory response which includes swelling. Deeper scratches that damage tissue more extensively tend to swell more as part of the healing process (source).
In most cases, swelling from a cat scratch is mild and subsides within a few days as the scratch heals. However, if the swelling is severe, accompanied by redness and warmth, or persists for over 24 hours, it could indicate infection that requires medical treatment.
When to Seek Medical Care for a Swollen Cat Scratch
It is normal for a cat scratch to swell slightly for the first 2-3 days, but you will want to seek medical care right away if the swelling gets worse or spreads during this time. Additionally, seek care if the wound starts oozing pus or becoming very red. While a little redness and mild discharge is normal, purulent drainage or severe redness indicates infection.
Lastly, if you start to run a fever or develop enlarged lymph nodes along with the swelling that doesn’t improve, plan to see your doctor promptly. The fever could indicate an infection has developed, such as cat-scratch fever. It’s important to seek medical attention as soon as possible in these cases, as antibiotics will be needed to treat the infection and prevent complications.
Treating Mild Swelling from a Cat Scratch
If the cat scratch is superficial and only results in mild swelling, you can often treat it at home. Here are some tips for treating mild swelling from a cat scratch:
Clean the wound thoroughly with soap and water. This helps remove dirt, bacteria, and debris that could cause infection. Be sure to gently clean around the wound as well. Pat dry with a clean towel.
Apply an antibiotic ointment like Neosporin to the scratch. This helps prevent infection from developing. Cover the scratch with a bandage or gauze pad to keep the ointment in place and protect the wound. Change the bandage daily.
Take an over-the-counter oral antihistamine like Benadryl to reduce swelling and itchiness. Antihistamines can help if the swelling is caused by an allergic reaction to the cat scratch.
Apply cool compresses to the swollen area. Wrap an ice pack or bag of frozen vegetables in a towel and apply to the scratch for 10-15 minutes several times a day. The cold helps constrict blood vessels and reduces inflammation.
Keep the wound clean and watch for signs of infection like increasing redness, heat, pus or foul odor. See your doctor if the swelling persists beyond a few days or gets worse.
Preventing Infection in Cat Scratches
To help prevent infection from developing in a cat scratch, it’s important to clean and care for the wound properly. Here are some tips:
Clean the wound immediately. As soon as you receive a cat scratch, wash the area thoroughly with soap and warm water. This helps remove debris, dirt, and bacteria from the wound.[1]
Apply antibiotic ointment. After cleaning, apply an over-the-counter antibiotic ointment like Neosporin to the scratch. Antibiotic ointments help prevent bacterial infection in wounds.[2]
Cover with a bandage. Bandaging the scratch helps keep the wound clean and prevents bacteria from entering. Change the bandage daily.[3]
Keep it clean and dry. Check the scratch daily and wash with soap and water if it gets dirty. Keeping it clean and dry helps prevent infection.[1]
When to Get a Tetanus Shot after a Cat Scratch
Cat scratches can sometimes lead to a bacterial infection called tetanus. Tetanus is caused when dirt, saliva, or feces gets into a puncture wound or deep scratch and infects it with the bacteria Clostridium tetani.
One way to prevent tetanus infection after a cat scratch is to stay up-to-date on your tetanus vaccinations. According to the Mayo Clinic, it’s recommended to get a tetanus booster shot if:
- You haven’t had a tetanus shot in the past 5 years
- The cat scratch is deep or punctured the skin
- The cat scratch shows signs of infection like redness, swelling, pus, red streaks, increased pain or warmth
Keeping your tetanus vaccinations current is the best way to prevent tetanus infection from a cat scratch. Speak to your doctor about getting a booster if it’s been over 5 years since your last shot or if the cat scratch is showing concerning symptoms.
Signs of Cat Scratch Fever
Cat scratch fever causes several common symptoms in those infected. The most notable signs and symptoms include:
- Swollen lymph nodes – The lymph nodes closest to the original cat scratch or bite will usually become swollen and tender within 1-3 weeks of the injury. This is often the first notable symptom.
- Fever – Low grade fevers of 100-104°F are common. Fevers may come and go.
- Headache – Moderate to severe headache pain often occurs.
- Fatigue – Exhaustion and tiredness are frequently reported.
- Poor appetite – Many people experience a decreased appetite.
In some cases, a rash may also develop around the scratch or bite. Joint pain, chills, muscle aches, and eye inflammation are also possible. In children, symptoms can be mild, but in adults cat scratch fever often causes a full week of high fever, headache, and lymph node swelling before improving.
Treating Cat Scratch Fever
Cat scratch fever usually goes away on its own within a few weeks, but antibiotics may be prescribed in some cases to speed healing and prevent complications (https://www.aafp.org/pubs/afp/issues/2011/0115/p152.html). The antibiotics azithromycin and ciprofloxacin are commonly used to treat cat scratch fever.
Over-the-counter medications like acetaminophen or ibuprofen can help relieve fever and body aches associated with cat scratch fever. Applying warm compresses to swollen lymph nodes may also provide relief from swelling and pain.
Most people fully recover from cat scratch fever within 2-4 months, even without antibiotics. Seeking prompt medical treatment can help manage symptoms and reduce the risk of rare complications like encephalitis.
When to See a Doctor for Cat Scratch Fever
It’s important to seek medical attention if you experience certain symptoms after a cat scratch. According to the Cleveland Clinic[1], you should see a doctor if the lymph nodes near the scratch become tender and swollen. Swollen lymph nodes can be a sign that the bacteria from the scratch has spread.
You should also see a doctor if you have a fever and fatigue that lasts more than 3-4 days after the scratch, according to Johns Hopkins Medicine[2]. This prolonged fever and fatigue can indicate an infection.
Additional symptoms that warrant a doctor visit include headache, sore throat, and rash, according to Healthline[3]. These could be signs of cat scratch fever developing. It’s important to get checked out to determine if antibiotics are needed.
Preventing Cat Scratch Fever
There are several precautions you can take to help prevent getting cat scratch fever:
Avoid rough play with cats. Rough play can cause deep scratches and bites, which increases the risk of infection. Be gentle when playing with cats and avoid handling cats that seem agitated or aggressive.
Carefully handle stray or feral cats. Stray and feral cats are more likely to carry Bartonella bacteria. If you need to handle a stray cat, wear gloves and wash your hands afterwards.
Wash your hands after contact with cats. Thoroughly washing hands with soap and water after petting, holding or playing with cats can remove bacteria and prevent transmission. Clean any scratches or bites right away with soap and water.
Keep cats indoors and free of fleas. Fleas can transmit Bartonella bacteria between cats. Keeping your cat indoors and using flea control measures reduces their risk of infection. Cats with flea infestations are more likely to spread bacteria when scratching.
Summary
In summary, mild swelling and redness can occur after a cat scratch due to the normal immune response, but keep an eye out for signs of infection like pus, red streaks, increased pain or swelling. Clean the scratch well with soap and apply antibiotic ointment. Seek medical care if symptoms worsen or don’t improve in a few days.
More serious swelling and lymph node inflammation may be signs of cat scratch fever. This bacterial infection causes flu-like symptoms and a rash. It is treated with antibiotics. Prevent cat scratch fever by keeping cats free of fleas and promptly cleaning any bites or scratches. The tetanus vaccine can help prevent other bacterial infections.
See a doctor right away if you have symptoms beyond mild swelling, such as pus, red streaks, tender lymph nodes or fever. While most cat scratches heal on their own, it’s important to monitor for signs of infection and get prompt treatment when necessary.