Cause: A bacterium called Haemophilus ducreyi.

Incubation Period: 12 hours to five days.

Transmission: Similar to transmission of syphilis and herpes. You can get chancroid in your mouth, throat, lips, anus, tongue, vagina, or penis. You can get it or spread it through intimate skin contact (direct skin-to-skin touching of open sores), or by secondary contact (for example through your hands or a dildo).

What to Look For: The picture above pretty much shows you what a chancroid looks like. The sores are painful and tender when touched. Usually, there will be sore, swollen glands near the affected area, too.

Remember the areas where they are most likely to appear. You can also get them on your thigh or hands from an open sore, but this is more difficult and rare than getting them on your genitals or mouth.

Treatment: Chancroid is completely curable by antibiotics.

Contact your health provider as soon as you think you may have gotten an STD; the sooner you are treated, the better your chances of recovery, and it is less likely you will get complications. Also, it is likely you will get complications. Also, have your partners checked out, and stop having sex until you get better. Otherwise, you and your partners could keep passing the disease back and forth to each other.

Complications: Spreading chancroid to other parts of the body (called "auto-innoculation") is considered a complication. This can happen with many STDs.

Women can have the bacteria that causes chancroids in their vagina, but no sores will ever be visible. These women are called "carriers" of the disease because they can spread it to other people, even though they don't have any symptoms themselves.

If you have chancroid in your urethra, sometimes an open channel can form (called a "fistula"). On the penis, it would almost be like having two openings where urine would flow through, except that the fistula is unnatural, and can be infected by other diseases.

Having an open sore makes it easier for secondary or opportunistic infections to happen. This is especially true for HIV, which can easily get into your body if your skin is broken. Also, if you have HIV and an open chancroid sore, then you are more likely to transmit HIV to another person.