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Leprosy is a chronic granulomatous disease.

Man with leprosy
Man with leprosy


  • mycobacterium leprae = intracellular parasite.
  • Incubation period
    • tuberculoid = 2-5 years
    • lepromatous = 8-11 years


  • Spread in nasal discharges to the skin or nose.
  • Infectivity is low (<10% those exposed show any signs of infection)


Geographical distribution of disease is patchy with 70% cases in India


Bacilli enter through the respiratory tract (usually) and multiply in peripheral Schwann cells (limbs and face)

  • Form of disease determined by level of cell mediated immunity:
  • High levels- tuberculoid disease
  • No/few skin/nerve lesions appear followed by spont. healing.
  • Absent-lepromatous diease
  • Other tissues also become involved (eyes, testes, kidneys, smooth
  • Muscle, reticuloendothelia system and vascular endothelium.


Clinical features

  • Skin lesions
  • Parasthesia
  • Thickenned peripheral nerves.


  • Often thought to cause loss of limbs (‚Äúskin falling off‚ÄĚ) but in recent times this is less of an issue.
  • Loss of sensation produces loss of protective reactions √†resulting in injury√†infection can develop and in the past (when not caught early) could result in the need for amputation.


*Early diagnosis is essential in preventing disability*

  • Clinical findings of one or more cardinal signs.
  • Biopsy of skin lesion or nerve.
  • AFBs on slit skin smears



Multi-drug regimen

  • Rifampicin
  • Dapsone
  • Clofazimine


  • Murtagh‚Äôs General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
  • Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
  • Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) FRACGP currently works as a GP and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University, and is studying for a Masters of Sports Medicine at the University of Queensland. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

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