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Everything You Need to Know About Chancroid

Chancroid is the STD that even your doctor will have a hard time diagnosing.
illustration chancroid
Theresa Chromati

Have a painful, pus-filled ulcer on your junk that doctors can't quite figure out? Intrigue is not always sexy, apparently. Your mysterious little sore could be the rare (like, really rare) and elusive chancroid.

What exactly is chancroid?
Chancroid is an infection caused by the bacterium Haemophilus ducreyi, the same genus as other pathogenic bacteria that can cause sepsis and meningitis in young children. If you've never heard of chancroid, that may not be surprising—today, it's pretty rare in the US. The number of cases dropped steadily between 1987 and 2001, according to the CDC; just 11 cases were diagnosed in the US in 2015. That's good news, since you likely won't ever have to see one (chancroid is not exactly the Javier Bardem of STDs) but we suggest you do a quick google image search—not while you're eating—just to stay informed.


A few days after a person is infected, chancroid might look like one or more little red sores. But after a few days, the sores blow up into what the CDC calls a "painful genital ulcer and tender suppurative inguinal adenopathy." That translates to a painful, grayish-yellow, pus-filled sore that may bleed if touched and can measure up to two inches across. In men, there's usually only one sore on the penis or scrotum, but in women there can be several that pop up on the labia, between the labia and anus, or on the thighs. At its worst, it may cause the whole groin area to swell, or cause pain during sex, urination, or pooping. In short, this thing is out to ruin all your fun. Luckily, it's fairly easy to oust (more on that in a minute).

Diagnosing chancroid is its own challenge. The symptoms are often confused with those of herpes and syphilis. If a doctor suspects a patient's symptoms are caused by chancroid, she would have no easy diagnostic test to use. Instead, she would have to send a sample to the lab, where researchers would culture the bacteria in a petri dish and look for its distinctive "school of fish" pattern. But there's a catch: H. ducreyi does not grow well in the lab, which means the test might come out negative even if the patient really does have chancroid. These days it's easier just to rule out the presence of other infections with similar symptoms, but it could mean that chancroid is being underreported.


Who gets it?
In the US, pretty much no one (we think). But technically, anyone can get it. H. ducreyi is transmitted through contact with an open sore, which can happen during sex or by simply touching it. It's more common in men than in women, particularly in uncircumcised males. A few years back, researchers tested a vaccine on rabbits, but it didn't work. Chancroid is on the decline worldwide, though there are still outbreaks in underdeveloped regions of Africa, Asia, and the Caribbean. In areas in which people have little or no access to medical care, chancroid can cause chronic skin infections, or run rampant through populations of sex workers.

How do you treat chancroid?
Since chancroid is caused by a bacterium, antibiotics do the trick. That should clear up the ulcer in a few days. If it's really bad, a doctor can puncture the ulcer with a needle to drain it. But since that doesn't sound like a spa treatment, so we recommend staying vigilant if you think you have this infection.

Mercifully, there is no evidence that H. ducreyi is becoming resistant to antibiotics, as are many disease-causing bacteria. It's important to treat it promptly because having an open sore like that can make it much easier to contract HIV.

How do I make sure I don't get it?
Like many other bacterial infections, condoms are your number one ally. Also, if you needed a reminder not to fool around with someone's junk on which there are open, visible sores, consider this it.

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