Snapshot A 48-year-old recent immigrant from Vietnam presents to the clinic with a four month history of a reddish skin patch on his back. He reports that it feels numb and is increasing in size. Past medical and drug history are unremarkable. Physical exam reveals an erythematous skin patch, located on the mid back. Lesion is 6 cm by 2.5 cm with well-defined margins and is insensate to light touch, temperature, and pin-prick. There are no thickened peripheral nerves and sensation, motor activity, and reflexes are intact in both upper and lower limbs. A punch biopsy of the lesion was taken for AFB and the local health authorities notified. Introduction Classification bacteria other bacteria Mycobacterium M. leprae Presentation Leprosy presents as a spectrum of disease between 2 extreme forms Lepromatous (LL) Tuberculoid (TL) Presentation Diffuse "Leonine facies" (nasal collapse, loss of eyebrows, lumpy earlobe) Skin hypopigmentation, thickening, and plaques Regional motor and sensory loss (bacteria invade Schwann cells) Testicular destruction Blindness Limited hypopigmented skin plaques Hair loss Decreased sensation. Cell-mediated immunity response Failed (TH2 respond, TH1 do not) Strong (TH1 respond appropriately) Communicable Yes No Sensation in extremities Completely lost Numbness Lepromin skin test No reaction +++ Amount of bacteria in tissue +++ + Evaluation Diagnosis lepromin skin test similar to PPD used for tuberculosis not used for diagnosis, but rather to place patients on spectrum of disease positive only in TL LL patients cannot mount a cell-mediate immune response punch biopsy acid-fast bacilli on biopsy of a hypopigmented, insensate skin lesion Differential Tinea corporis Keloids Cutaneous lupus erythematosus Neurofibromatosis Mycosis fungoides Treatment Dapsone given orally long term toxicity is hemolysis and methemoglobinemia Alternate treatments rifampin + dapsone for tuberculoid form clofazimine + dapsone for lepromatous form Prognosis, Prevention, and Complications Prognosis Early diagnosis and treatment crucial to prevent loss of limbs Prevention clinical management of active cases annual evaluation of household contacts BCG vaccine provdes partial protection in endemic areas given at birth Complications repeated injuries lead to eventual loss of limb and deformity