Leprosy

Introduction. 

Leprosy (Hansen's Disease) is a slow degenerative disease brought on by the patient's immune response to Mycobacterium leprae. In patients with a healthy cell-mediate immune response, there are few bacilli present (= paucibacillary) and tuberculoid skin lesions are present. In the lepromatous form, many bacteria are observed (multibacillary) due to a defective cell-mediated immunity. Nerve damage and tissue destruction result.

Summary

• Cause: Mycobacterium leprae
• Microscopy: Gram-positive rods, acid-fast
• Symptoms: tuberculoid: hypopigmented skin lesions; lepromatous: destructive skin lesions on trunk, face, nose; neuropathy
• Transmission: aerosols or contact with nasal secretions; contact with armadillos
• Pathogenesis: Intracellular pathogen; survive in phagolysosome. Immunopathogenesis
• Treatment::Dapsone + rifampicin (+clofazimine for lepromatous form)