If You Notice a Blister Here, Get a Blood Test, Experts Say


Your skin can serve as a window to your health—especially when it's flaring up with abnormal symptoms. Now, experts from the Centers for Disease Control and Prevention (CDC) are warning the public about a serious but preventable condition which causes blisters on the skin in one location in particular. Their experts say that if you notice a blister in this spot, you should request a blood test to be screened for a potentially life-threatening disease which affects roughly 12,000 people per year, hospitalizing 500. Read on to find out what to look for, and to learn whether you're at high risk of complications.

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Your cat's scratches could be worse than you thought.
Shutterstock/Maria Sivtseva

Even if your cat is your closest companion, they may still bite or scratch for a wide range of reasons. As natural predators, many cats attack instinctively when they are afraid, showing dominance, or as a form of play. However, experts warn that there can be potentially serious consequences if your cat breaks the skin while biting or scratching. In particular, it's important to call a doctor and request a blood test to screen for cat scratch disease (CSD) if you notice a blister at the site of a wound.

According to the CDC, signs of CSD most typically appear roughly 14 days after infection. "The infected area may appear swollen and red with round, raised lesions and can have pus," the health organization explains.

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CSD is more common in cats than you might think.
Shutterstock/SJ Duran

CSD is caused by a bacterium known as Bartonella henselae (B. henselae). According to the CDC, roughly 40 percent of cats become infected with B. henselae over the course of their lives, and many show no symptoms of illness. "Kittens younger than one year are more likely to have B. henselae infection and to spread the germ to people. Kittens are also more likely to scratch and bite while they play and learn how to attack prey," the CDC warns.

Your cat can also give you CSD by licking a pre-existing wound, meaning transmission can occur without a skin-breaking bite or scratch. If you notice this symptom and have a cat in your home, your doctor may wish to rule out CSD.

Look out for these other symptoms of cat scratch disease.

Blisters or lesions at the site of a wound are the most common signs of CSD, but the CDC says there are several other signs that you may have contracted the illness. "A person with CSD may also have a fever, headache, poor appetite, and exhaustion," the health authority writes. "Later, the person's lymph nodes near the original scratch or bite can become swollen, tender, or painful," their experts add.

Though rare, some individuals may go on to develop serious complications of CSD which can affect the brain, eyes, heart, or other internal organs, the CDC warns. Children between the ages of five and 14 as well as immune-compromised individuals are at greatest risk of developing complications of CSD.

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Here's what you can do about it.

If you have a cat at home, it's important to take preventative measures against cat scratch disease. The best way to avoid CSD is to avoid bites and scratches in the first place by giving your cat physical distance when they're being aggressive or playing in such a manner. The CDC also recommends always washing any cat bites and scratches with soap and running water, and washing your hands thoroughly after playing with your pet.

Experts also warn that cats often become infected with B. henselae bacteria if they've come in contact with fleas. For this reason, it's essential to treat flea infestations quickly to limit exposure to the dangerous bacteria. "Use adequate flea control and keep your cats indoors," Christina Nelson, MD, a medical epidemiologist with the CDC told NPR in 2016.

Speak with your vet and doctor for more information on how to prevent cat scratch disease in your cat and yourself.

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