• Also known as Hansen's Disease
  • Infectious disease caused by Mycobacterium leprae
  • Most new cases found in developing countries
    • Level 3 Countries with higher numbers of cases include: India, Brazil, Indonesia, Bangladesh, Nigeria
  • Means of transmission not fully understood - likely respiratory.
  • Has variety of clinical and histopathologic manifestations due to broad range of cellular immune response


  • Disease spectrum ranges from strong immune reaction and few organisms (tuberculoid) to weak immune reaction and numerous organisms (lepromatous)
  • Categories
    • Tuberculoid (TT)
    • Borderline tuberculoid (BT)
    • Mid-borderline (BB)
    • Borderline lepromatous (BL)
    • Lepromatous (LL)
    • Indeterminate (I)

Risk Factors

  • Close contact with infected person
    • Type of leprosy in the contact (lepromatous may be more contagious than tuberculoid)
  • Armadillo exposure
  • Increased age
  • Genetic influences

Clinical Features

  • Hypopigmented or red patches of skin
    • Diminished sensation or lost sensation within patches
  • Paresthesias
  • Painless wounds on hands or feet
  • Lumps on earlobes or face
  • Tender, enlarged peripheral nerves

Consider leprosy in patients who have skin lesions that do not respond to conventional treatments or when there are associated sensory disturbances

Differential Diagnosis


  • Diagnosis made by skin biopsy




  • Immunologic reaction that can occur before or during treatment. Presentation can include: fatigue, malaise, fever, neuritis, arthritis, iritis, nasopharyngeal symptoms

External Links

See Also