Chancroid Overview

Chancroid is a highly infectious bacterial disease caused by Haemophilus ducreyi that affects the skin and mucous membranes of the penis, vulva, urethra, and anus. It produces painful irregularly shaped nonsyphilitic ulcers (called chancroids, soft chancres, or soft sores) that may heal without treatment.

Incidence and Prevalence of Chancroid

According to the Centers for Disease Control and Prevention (CDC), the number of reported cases of chancroid in the United States each year has fluctuated since 2001. In 2012, a total of 15 new cases were reported; however, Haemophilus ducreyi is difficult to culture so the condition may be significantly underdiagnosed.

Causes and Risk Factors for Chancroid

A person who has a chancroid sore may transmit the disease during vaginal, anal, or oral sex. Ejaculation is not necessary for infection to spread. An uncircumcised man is more likely to contract the disease, because foreskin may hinder hygiene, hide sores, and promote the spread of bacteria. The disease cannot be spread to infants during childbirth.

Signs and Symptoms of Chancroid

First signs of infection typically appear 3 to 5 days after exposure, although symptoms can take up to 2 weeks to appear. Initially, a tender bump develops at the site of contact. After 1 or 2 days, the bump develops into one or more shallow sores (ulcers) that break open, deepen, and become inflamed. Ulcers are pus filled, painful, and may persist for several weeks. In men, they are most common at the base of the head of the penis (glans), though they can appear on the penis shaft. In women, ulcers are typically found on the labia and near the clitoris.

Less commonly, infection spreads to the scrotum, perineum (between scrotum or vagina and anus), anus, rectum, and thighs. Touching the ulcers can transfer bacteria to the fingers, which can transfer bacteria to other areas, including the mouth, during contact. Anal sores may bleed and cause pain during defecation.

Men often develop one to four sores on the penis, and foreskin may swell. Women may develop ulcers around the vagina and rectum and may experience vaginal discharge. Painless sores can also develop on the cervix.

In about 50% of cases, mostly men, the lymph nodes in the groin develop into inflamed, pus-filled swellings (buboes) that can develop and enlarge until they burst the skin. They drain continuously, remain open, and can become infected by other bacteria. The infection can spread to other parts of the body by scratching or rubbing. A burst bubo can take months to heal completely.

Open ulcers increase the risk for contracting other STDs, including HIV.

Chancroid Diagnosis

The presence of Haemophilus ducreyi, seen under a microscope, indicates the disease. Diagnosis is often confirmed by a culture or biopsy of an ulcer. Although the bacteria do not enter the bloodstream, a blood test is performed to rule out or identify the presence of other STDs, including syphilis and genital herpes.

Treatment for Chancroid

Chancroid has become resistant to penicillin and tetracycline. Regular doses of erythromycin, trimethoprin, or ciprofloxacin are given for up to 2 weeks. Alternatively, azithromycin or ceftriaxone may be given in a single dose. A follow-up examination is typically required 7 days after starting treatment. Healing usually takes 10 to 11 days, but may take 2 weeks. Buboes may need to be drained with a needle (aspirated) under local anesthesia and scarring may occur from those that burst on their own.

Chancroid is a local infection that has no long-term effects. Recurrence is experienced in less than 10 percent of cases and may result from improper use of medication (e.g., not taking the entire prescription), a weakened immune system, or re-exposure to the bacteria through recently healed skin.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 10 Jun 1998

Last Modified: 13 Mar 2014