By:Brookelyn Nicole Norman

Synonyms for yaws

*Mothers yaws or crab yaws are the most common synonyms.

signs & symptoms

Stage 1 yaws typically occurs in early childhood, with peak incidence at about six years of age. A single itchy, strawberry-like growth appears on the skin over which a thin yellow crust forms (papillomatous lesion). This growth, the “mother yaw”, appears at the spot where the organism entered the body (inoculation site), typically on the leg or foot.

Stage 2 yaws typically follows several weeks or months after the initial symptoms. Similar skin sores appear on the face, legs, arms, and/or around the rectum and genitals. These sores usually heal slowly and may recur. Lesions on the bottom of the feet may produce painful cracks and ulcerations (keratosis), resulting in an awkward “crab-like” walk or “crab yaws.”

At this stage, swollen glands (swollen lymph nodes) are not uncommon and the rash may develop a brown crust.

The symptoms of stage 3 yaws occur in only about 10% of the people who are infected and may follow a dormant period of several years. Painful ulcers or nodules may develop on the skin (cutaneous) and cause facial disfigurement. Painful, granular sores (gummatous lesions) may also develop on the bones, especially the long bones of the legs (tibia). Painful skin and bone nodules may impair joint function and mobility.

Stage 3 yaws may also produce different and distinct syndromes. One, known as goundou syndrome, is characterized by inflammation and swelling of the tissues surrounding the nose (paranasal swelling), as well as overgrowth of the bones in the same region of the face (hypertrophic osteitis). Another, known as gangosa syndrome (also known as rhinopharyngitis mutilans), is characterized by degenerative changes of the nose, throat (pharynx), and the roof of the mouth (hard palate).

General Description

Yaws is an infectious tropical disease caused by the spirochete (spiral shaped) bacterium known as Treponema pertenue. The disease presents in three stages of which the first and second are easily treated.The skin may break open, forming an ulcer. The second stage (usually starting several weeks or months after the first) presents with a crispy, crunchy rash that may cover arms, legs, buttocks and/or face. If the bottoms of the feet are involved, walking is painful and the stage is known as "crab yaws."

Causes of Yaws

Yaws is an infectious disease caused by a spiral-shaped bacterium (spirochete) known as Treponema pertenue. Yaws is usually transmitted by direct contact with the infected skin sores of affected individuals. In some cases, yaws may be transmitted through the bite of an infected insect

Affected populations

Common infectious disease among children living in the tropical areas of Africa, South and Central America, the West Indies, and the Far East. It is not known in the United States. Yaws affects males and females in equal numbers and is most common in children between the ages of six and 10.

Related disorders

Bejel is an infectious disease which is rare in the United States but common in certain parts of the world. It is characterized by lesions of the skin and bones and is caused by a bacteria known as Treponema pallidum II. The infection is very similar to syphilis but is not sexually transmitted. Children with Bejel have patchy ulcerations of mucous membranes particularly in or near the mouth. (For more information on this disorder, choose “Bejel” as your search term in the Rare Disease Database.)


Yaws is suspected in any child who has the characteristic clinical features and lives in an area where the disease is common. With increasing travel, a child once in the tropics may carry the disease to a more temperate area of the world.Laboratory confirmation of the diagnosis is by blood serum tests (for example, RPR or rapid plasma reagent test, VDRL test or venereal disease research laboratory test, TPHA or Treponema pallidum hemagglutination test, FTA-ABS or fluorescent treponemal antibody absorption), but most frequently the diagnosis is made on clinical findings.

Standard therapies

Stage 1 and 2 yaws is treated with antibiotics, especially with benzathine penicillin. A single large dose of these medications usually heals the skin lesions and eliminates the organism. These antibiotic drugs may also be used to prevent this disease in family members and others who are in frequent contact with affected individuals. At the present time, there is no treatment for the destructive bone lesions or scars associated with stage 3 yaws.

Supporting organizations

Genetic and Rare Diseases (GARD) Information Center