Yaws

What is yaws?

Yaws is an infectious disease that affects the skin and bones. It's a tropical illness that was once common in West Africa, Indonesia, New Guinea, the Solomon Islands, Haiti, Dominica, Peru, Colombia, Ecuador, and parts of Brazil. In these countries, yaws most often affects children between the ages of 2 and 5, especially children who wear few clothes, have frequent skin injuries, and live in areas of poor hygiene.

During the 1950s, yaws was a common tropical illness, infecting 50 million to 100 million people. Since that time, the World Health Organization (WHO) has battled yaws in many tropical areas of the world. More than 160 million people have been examined in 46 countries, and more than 50 million cases of yaws have been treated with penicillin. As a result, the incidence of yaws declined dramatically worldwide. This disease always has been extremely rare in the United States.

Yaws is caused by a subspecies of Treponema pallidum, the bacterium that causes syphilis, a sexually transmitted disease. However, yaws is not transmitted sexually. Also, unlike syphilis, yaws does not have the potential to cause long-term damage to the heart and cardiovascular system. Yaws almost always is transmitted by direct contact with infected skin. Yaws has three stages:

• Early yaws: About three to five weeks after a person is exposed to yaws, a raspberry-like bump appears on the skin, commonly on the legs or buttocks. This bump, sometimes called a frambesioma or mother yaw, will gradually grow larger and form a thin yellow crust. The area can itch, and there can be swollen lymph nodes (swollen glands) nearby. The bump usually heals on its own within six months, and it often leaves a scar.
• Second-stage yaws: The next stage may begin while the mother yaw is still present, or it may not start until several weeks or months after the first stage of yaws heals. In this stage, a crusty rash forms that can involve the face, arms, legs, and buttocks. The bottoms of the feet also can become covered with painful, thick sores. Walking can become painful and difficult. Although the bones and joints also can be affected, second-stage yaws usually does not cause destruction in these areas.
• Late yaws: Late yaws develops in only about 10% of people who are infected with yaws. It begins at least five years after early yaws starts, and it can cause severe damage to the skin, bones, and joints, especially in the legs. Late yaws also can cause a form of facial disfiguration called gangosa or rhinopharyngitis mutilans as it attacks and destroys parts of the nose, upper jaw, palate (roof of the mouth), and part of the throat called the pharynx. If there is swelling around the nose, a person with late yaws can have headaches and nasal discharge.

Symptoms of yaws

Symptoms of yaws include:

• a single, itchy, raspberry-like growth (mother yaw) on the skin, usually on the legs or buttocks, which eventually develops a thin, yellow crust
• swollen lymph nodes (swollen glands)
• a rash that forms a brown crust
• bone and joint pain
• painful bumps or sores on the skin and on the soles of the feet
• facial swelling and disfiguration (in late yaws).

Diagnosing yaws

Your doctor may suspect that you have yaws based on your travel history, your symptoms, and the results of your physical examination. To confirm the diagnosis, he or she will order blood tests to check for evidence of an infection with the bacteria that cause yaws. Your doctor also may take a sample of tissue from a skin sore. This sample will be examined in a laboratory for T. pallidum bacteria.

Expected duration of yaws

The mother yaw often heals quickly with treatment. Without treatment, it usually heals on its own within six months. Later, in second-stage and late yaws, rashes and lesions are more severe and last longer. Without treatment, the symptoms can return over many years.

Preventing yaws

If you have come in close contact with someone who has yaws, your physician may recommend that you receive penicillin or another antibiotic, usually oral azithromycin, to prevent infection.

Treating yaws

People with yaws usually are treated with a single shot of penicillin or oral azithromycin.

When to call a professional

Call your doctor if you have symptoms of yaws, especially if you have visited a tropical country.

Prognosis

Treatment of yaws is usually successful.

Additional info

National Institute of Allergy and Infectious Diseases (NIAID)
https://www.niaid.nih.gov/

Centers for Disease Control and Prevention (CDC)
https://www.cdc.gov/