Yaws, Bejel, and Pinta

Yaws, bejel, and pinta are endemic, nonvenereal treponematoses. The causative organisms are Treponema pallidum pertenue (yaws), T. pallidum endemicum (bejel), and T. carateum (pinta). These treponematoses are generally transmitted by direct skin-to-skin contact with infected skin lesions. Yaws and bejel affect skin and bones, resulting in cutaneous plaques and nodules and destructive bone lesions. Pinta involves only the skin. Diagnosis is made with a combination of serology, clinical features, demographics, and geographic distribution. Management includes intramuscular benzathine penicillin G or oral azithromycin.

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Epidemiology and Etiology


Yaws (most common):

  • Prevalent in hot, humid areas of: 
    • South Asia
    • Indonesia
    • Pacific Islands
    • Africa
    • South America
  • Children > adults


  • Prevalent in arid regions of:
    • Middle East
    • Central and South Africa
  • Children > adults


  • Very rare
  • Occurrence has declined.
  • May still be endemic in:
    • South America
    • Central America
  • Teenagers and adults > children


  • Causative organisms: 
    • Subspecies of Treponema pallidum:
      • Yaws: T. pallidum pertenue (yaws)
      • Bejel: T. pallidum endemicum (bejel)
    • T. carateum (pinta)
  • Basic Treponema characteristics:
    • Spirochete (spiral shaped)
    • Gram negative

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Humans are the only reservoir.


  • Yaws: skin-to-skin contact with lesions
  • Bejel:
    • Skin-to-skin contact with lesions
    • Mouth-to-mouth contact with oral lesions
    • Fomites (e.g., utensils for eating and drinking)
  • Pinta: skin-to-skin contact with lesions


  • Skin contact with an infected lesion → spirochete adheres to the skin or mucosal membranes
  • Production of hyaluronidase → allows for tissue invasion
  • Organisms coat themselves in the host’s fibronectin → prevents phagocytosis and recognition by the immune system
  • Travel to lymph nodes → dissemination through the bloodstream
  • Host immune response → disease manifestations
Pathogenesis of Treponema infections

Pathogenesis of Treponema infections:
The pathogen adheres to the skin or mucosal membranes, leading to the production of hyaluronidase, which allows for tissue invasion. The pathogen coats itself in the host’s fibronectin, which prevents its phagocytosis and recognition by the immune system. Consequently, the pathogen disseminates through the bloodstream. A host immune response ultimately occurs, which causes disease manifestations.

Image by Lecturio.

Clinical Presentation


Primary phase:

  • Localized papule at the site of inoculation (“mother yaw”):
    • Most commonly occurs on the lower extremities
    • Painless
    • May be pruritic
  • Evolution:
    • Progresses to a large, yellow nodule
    • Possible ulceration with red granulation tissue at the ulcer base
    • Regresses spontaneously into a hyperpigmented scar

Secondary phase:

  • Secondary lesions may be:
    • Solitary, ulcerated nodules resembling primary yaws
    • Multiple smaller nodules
  • Painful palmar and plantar papilloma or plaques
  • Arthralgias
  • Osteoperiostitis:
    • Nocturnal bone pain
    • Dactylitis

Tertiary phase:

  • Gummatous lesions (destructive, granulomatous lesions) of:
    • Skin
    • Bones
  • Destructive, mutilating lesions can lead to:
    • Long-bone malformations (e.g., bowed tibia)
    • Juxtaarticular cutaneous or subcutaneous lesions
    • Ulcerations of the nasopharynx and palate (“rhinopharyngitis mutilans”)
    • Exostosis of the nasal portion of the maxilla (“goundou”)


Primary phase:

  • Small, primary papule, patch, or ulcer on the oral mucosa
  • Not commonly seen due to small size
  • Resolves spontaneously

Secondary stage:

  • Painless ulcers or patches:
    • Can affect:
      • Mucous membranes
      • Skin (particularly warm, moist regions)
    • Become condylomatous before eventually healing
  • Periostitis → bone pain
  • Laryngitis → hoarseness 
  • Nasopharyngeal ulcers
  • Possible genital ulcer similar to that seen in syphilis

Tertiary phase:

  • Gummatous lesions of:
    • Skin
    • Bones
  • Destructive lesions result in:
    • Bone deformities
    • Nasopharyngeal destruction
    • Juxtaarticular nodules


Primary phase:

  • Initial red papule or plaque:
    • Pruritic
    • Commonly on lower extremities
    • Satellite lesions may be present.
  • Regional lymphadenopathy

Secondary phase: pintids

  • Multiple pruritic plaques undergo a color change from red to gray to black.
  • Similar to the initial skin lesion of the primary phase

Tertiary or late phase:

  • Skin discoloration and depigmentation
  • Atrophy
Cutaneous lesions of pinta

Cutaneous lesions of pinta (Treponema carateum infection)
A: erythematous plaque of early pinta
B: skin discoloration of late pinta

Image: “Endemic treponemal diseases” by Marks M, Solomon AW, Mabey DC. License: CC BY 4.0

Diagnosis and Management


Because these treponemal species are morphologically indistinguishable, the diagnosis is based on the combination of demographics, geographic region, clinical presentation, and laboratory findings.


  • Nontreponemal tests:
    • Options:
      • Rapid plasma reagin
      • VDRL
    • Titers should decline after treatment. 
  • Treponemal tests:
    • Options:
      • Fluorescent treponemal antibody absorption test (FTA-ABS)
      • Microhemagglutination test for antibodies to T. pallidum (MHA-TP)
      • T. pallidum particle agglutination test
      • T. pallidum enzyme immunoassay
      • Chemiluminescence immunoassay
    • Cannot differentiate between current and previous infection (titers stay positive after treatment)

Direct methods:

  • PCR:
    • Detect Treponema DNA
    • Specimen: swabs of an ulcer
  • Dark-field microscopy:
    • A microscopy technique that illuminates specimens against a dark background
    • Motile spirochetes will be seen.


Treatment is the same for all of these infections. Options include:

  • Intramuscular benzathine penicillin G (preferred with bejel and pinta)
  • Oral azithromycin

Differential Diagnosis

  • Syphilis: a sexually transmitted bacterial infection caused by T. pallidum pallidum. Syphilis has 3 stages. Primary syphilis presents with a painless genital ulcer called a chancre. Secondary syphilis presents with diffuse rash, condylomata lata, and flu-like symptoms. Tertiary syphilis presents with neurological and cardiac involvement. Diagnosis is with nontreponemal and treponemal serological tests. The mainstay of treatment is intramuscular benzathine penicillin G.
  • Chancroid: a sexually transmitted infection caused by Haemophilus ducreyi. Chancroid presents with painful genital ulcers and suppurative inguinal lymphadenopathy (buboes). Diagnosis is usually clinical, though PCR and cultures can help (if available). Treatment is with macrolide antibiotics.
  • Leishmaniasis: an infection caused by Leishmania species, which are obligate intracellular parasites transmitted by the sandfly. The mildest form is cutaneous leishmaniasis, which is characterized by painless skin ulcers. The mucocutaneous type involves more tissue destruction and deformities. Visceral leishmaniasis (VL) presents with hepatosplenomegaly, anemia, thrombocytopenia, and fever. Management is based on the clinical severity. Systemic treatment (amphotericin B) is needed for VL. 
  • Leprosy: a chronic bacterial infection caused by Mycobacterium leprae complex. Symptoms primarily affect the skin and peripheral nerves, resulting in cutaneous manifestations (e.g., hypopigmented macules) and neurologic manifestations (e.g., loss of sensation). Diagnosis is established clinically and supported with skin biopsy. Management includes long-term multidrug antibiotic combinations.


  1. Mitjà, O., Mabey, D. (2019). Yaws, bejel, and pinta. Uptodate. Retrieved May 9, 2021, from https://www.uptodate.com/contents/yaws-bejel-and-pinta
  2. Galadari, H. (2021). Yaws: Background, etiology and pathophysiology, epidemiology. Medscape. Retrieved May 9, 2021, from https://emedicine.medscape.com/article/1053612-overview
  3. Fine, S.M. (2021). Treponematosis (Endemic syphilis, yaws, and pinta): Background, pathophysiology, epidemiology. Medscape. Retrieved May 10, 2021, from https://emedicine.medscape.com/article/230403-overview
  4.  Maxfield, L. Crane, J.S. (2020). Yaws. Stat Pearls. https://pubmed.ncbi.nlm.nih.gov/30252269/
  5.  Torok, E. (2009). Oxford Handbook of Infectious Diseases and Microbiology (1st ed.). Oxford University Press. p. 388. ISBN 978-0-19-856925-1
  6. Bush, L.M., Vazquez-Pertejo, M.T. (2020). Bejel, pinta, and yaws. MSD Manual Professional Version. Retrieved May 18, 2021, from https://www.msdmanuals.com/professional/infectious-diseases/spirochetes/bejel,-pinta,-and-yaws

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