Leprosy Diagnosis

How is it Diagnosed?

Based on presence of any one of the following Cardinal signs.

Sr. No Cardinal Signs Method of Eliciting
1 Hypopigmented or reddish Skin lesion(s) with definite loss of sensation Anaesthesia on the patch to be elicited by testing for touch, pain and temp. sensation
2 Thickening of peripheral nerves with loss of sensation and weakness of the muscles of the hands, feet or face Examination of peripheral nerves e.g 1) Greater Auricular 2) Radial 3) Ulnar 4) Median 5) Lateral Popliteal 6) Posterior Tibial etc.
3 Demonstration of Mycobacterium Leprae (M.leprae) in the lesions Acid fast staining and examination Under oil immersion microscope

The first two cardinal signs can be identified by clinical examination alone while the third by examination of the slit skin smear under the microscope. Bacteriological examination has been discontinued in the programme.

Pre–requisites of Good Clinical Examination
  • Assurance & counseling of patients and/or family.
  • Essentially in good daylight.
  • Exam. of whole body with courtesy & respect to patient’s privacy.
  • Examination of female patient as far as possible by a female doctor or at least in the presence of one female.
Clinical Examination
  • The location of skin lesions be marked on a simple body outline.
  • One or few typical skin lesions should be tested for loss of sensation.
  • The main peripheral nerve trunks should be palpated to certain any thickening and tenderness.
  • Eyes, hands and feet should be examined.
Field classification of leprosy for purpose of MDT
Clinical Manifestation PB (Pauci–Bacilli) MB (Multi Bacillary)
Skin Lesion Upto 5 lesion 6 and above
Nerve involvement No nerve involvement or only one nerve involvement more than one nerve trunk involvement