A chancroid culture is used to determine if you have a sexually transmitted infection (STI) known as chancroid. Chancroid is caused by Haemophilus ducreyi. It can only be transmitted through sexual contact. Chancroid causes fluid-filled ulcers on the genitals.
A chancroid culture requires a small sample of skin from a chancroid ulcer. Any bacteria found in this sample are then grown in a lab. According to an article in the Canadian Journal of Infectious Disease Medicine (CJIDM), most laboratories consider chancroid culture the “gold standard” for diagnosing this STI (CJIDM 2011).
Chancroid is rare in the United States. According to the National Institutes of Health (NIH), less than 50 cases are diagnosed in the United States every year. The STI is more common in developing countries. Most U.S. citizens who have chancroid get it while travelling abroad (NIH, 2011).
Chancroid is often mistaken for more common STIs such as syphilis and herpes.
Call your doctor if you have symptoms of chancroid. You may also need testing if you have engaged in high-risk, unprotected sexual behavior.
According to the Illinois Department of Public Health (IDPH), chancroid usually appears as a small bump about 10 days after contact with the bacteria (IDPH, 2008). The bump grows into a soft ulcer. This ulcer often drains pus and fluid.
Characteristics of the ulcer include:
- 1/8 inch to 2 inches across
- soft (unlike syphilis sores, which are hard and rubbery)
- ragged gray, or yellowish edges
- bleeds easily at the base
On men, the ulcer appears on the:
- behind or on the head of the penis
- shaft or opening the penis
On women, ulcers usually develop on the outer vaginal lips. They may also occur on:
- the inner vaginal lips
- the perineal area (between the genitals and the anus)
- the inner thighs
Women may have as many as four or more ulcers. About half of men have only one ulcer.
Women often show no symptoms. They may experience pain during urination and intercourse. The ulcers may not be obvious.
Your healthcare provider will take a sample from an ulcer. This is often done with a cotton swab. The swab is taken to a laboratory where a technician will attempt to grow (culture) the Hemophilus ducreyi bacteria. The swab needs to reach a laboratory quickly. Otherwise, the bacteria will die.
Chancroid can go away without treatment. However, this can take one to three months. Scarring may occur.
Chancroid will generally go away much faster with antibiotics. The following antibiotics are commonly prescribed to treat chancroid:
If lymph nodes are infected, they may need to be drained. This can be done with localized surgery or a needle.
It is recommended that sexual activity be discontinued until the ulcers have healed completely.
A chancroid infection increases your risk of HIV. People who already have HIV and get chancroid may experience slow healing. They may also require more treatment. Half of people with chancroid will develop swollen inguinal lymph nodes. These are the lymph nodes near the groin.
Swollen inguinal lymph nodes may break through the skin and form a large, hard abscess. This is called a bubo. A bubo requires surgical drainage. If the bubo breaks open, it may become infected with bacteria.
If you are uncircumcised, scar tissue from the ulcer can cause phimosis. This tightens the foreskin so that it cannot retract. Circumcision may be needed to fix the problem.
Chancroid can be treated easily with antibiotics. It may get better without treatment, but this can be a long and uncomfortable process. Antibiotics help clear the ulcers quickly without leaving scars.
Treatment reduces your risk of acquiring HIV.
The only way to guarantee you do not get chancroid is to avoid all forms of sexual activity.
You may reduce your risk of getting chancroid and other STIs by engaging in safer sex practices. Use of a male or female condom at all times during each sexual encounter is strongly urged.