Yaws, Bejel, and Pinta

Epidemiology and Etiology

Epidemiology

Yaws (most common):

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

Bejel:

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

Pinta:

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

Etiology

• 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

Pathogenesis

Reservoir

Humans are the only reservoir.

Transmission

• 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

Pathophysiology

• 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

Clinical Presentation

Yaws

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”)

Bejel

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

Pinta

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

Diagnosis and Management

Diagnosis

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

Serology:

• 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.

Management

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.