Yaws

Key Features

• A contagious disease largely limited to tropical regions that is caused by Treponema pallidum subspecies pertenue

• Acquired by direct nonsexual contact, usually in childhood, although it may occur at any age

Clinical Findings

• Characterized by granulomatous lesions of the skin, mucous membranes, and bone

• The "mother yaw," a painless papule that later ulcerates, appears 3–4 weeks after exposure

• Regional lymphadenopathy is usually present

• Secondary lesions that are raised papillomas and papules

  • Appear 6–12 weeks later

  • Weep highly infectious material

  • Last for several months or years

• Painful ulcerated lesions on the soles are called "crab yaws" because of the resulting gait

• Late gummatous lesions may occur, with associated tissue destruction involving large areas of skin and subcutaneous tissues

• Late effects of yaws may be confused with similar changes occurring in leprosy and include

  • Bone change

  • Shortening of digits

  • Contractures

• Central nervous system, cardiac, or other visceral involvement is rare

Diagnosis

• Organisms can be demonstrated in infectious lesions with darkfield microscopy or immunofluorescence but cannot be cultured in artificial media

• Serologic tests for syphilis are positive

Treatment

• If untreated, may lead to chronic disability and disfigurement

• Penicillin, 2.4 million units of benzathine penicillin G intramuscularly is generally curative in any stage of the non–sexually transmitted treponematoses

• In cases of penicillin hypersensitivity, tetracycline, 500 mg orally four times a day for 10–14 days, is the recommended alternative