Leprosy (also known Hansen’s Disease) is an infectious disease caused by Mycobacterium leprae which involves the skin and peripheral nerves.

1. Leprosy ( Hansen’s disease )
Turki M. Alanazi

2. objectives
• Definition.
• Overview.
• Modes of transmission
• Risk factors.
• Clinical features.
• Types/classifications.
• Diagnosis
• Pathogenesis
• Treatment.
• Complications.
• Epidemiology & preventions.

3. What is leprosy ?
• Leprosy (also known Hansen’s Disease) is an infectious disease
caused by Mycobacterium leprae which involves the skin and
peripheral nerves.

4. History of leprosy
• Leprosy was recognized in the ancient civilizations of
China, Egypt and India.
• The earliest documented account of leprosy is around
1550 B.C on Egyptian papyrus.
• Through out history, the badly affected have often been
hated by their communities and families.

5. CONT..
• Discovered by Gerhard Armauer Hansen in 1873.
Global Project on the History of Leprosy
http://www.leprosyhistory.org/graphics/gallery/hansen.jpg

6. Overview
• Key facts about
leprosy :
▫ Leprosy is a chronic
infectious disease
caused by an acid-fast,
rod-shaped bacillus,
Mycobacterium leprae.
▫ Unlike other
mycobacteria, it does
not grow in artificial
media or even in tissue
culture.
Scollard, DM et al. 2006. “The continuing challenges of leprosy.”
Clinical microbiology reviews 19, no. 2: 338-81.

7. Facts …
• M. leprae multiplies very slowly and the incubation period of
the disease is about five years. (average 3 yrs)
• Symptoms can take as long as 20 years to appear.
• Leprosy is not highly infectious.
• Leprosy is transmitted via droplets, from the nose and mouth,
during close and frequent contacts with untreated cases.
• Untreated, leprosy can cause progressive and permanent damage to
the skin, nerves, limbs and eyes.

8. Transmission
• The exact mechanism of transmission of leprosy is
not known.
• the most widely held belief is that the disease is
transmitted by contact between cases of leprosy and
healthy persons.
• & Transmission nasal discharges (droplets).
• Leprosy is known to occur at all ages ranging from
early infancy to very old age.

9. Risk Factors for Leprosy
• Close contact — Contacts of patients with leprosy have a higher risk
of developing leprosy than the general population
• People who live in the areas where leprosy is endemic
 (parts of India, China, Japan, Nepal, Egypt, and other areas) and
especially those people in constant physical contact with infected
people.
• Immunity – immunocompromised individuals are more
susceptible to infection.
• Genetic influences - There is some evidence that genetic defects in
the immune system may cause certain people to be more likely to
become infected (region q25 on chromosome 6).
• Armadillo exposure — Leprosy is enzootic in the nine-banded
armadillo

10. Classification of Leprosy
• Two types of classification :
▫ Skin smear result classification. ( WHO )
▫ Clinical classification. (Ridley Jopling)

11. Classification of Leprosy
▫ Skin smear result (WHO) classification :
• 1- Paucibacillary leprosy (PB) – few Bacilli;
• Two to five skin lesions with negative skin smear results at all
sites.
• 2. Multibacillary leprosy (MB);
• Any form of leprosy in which the patient shows positive
smears at any site

12. Classification of Leprosy
Clinical (Ridley Jopling) classification :
1. Indeterminate leprosy (IL)
2. Tuberculoid leprosy (TT)
3. Lepromatous leprosy (LL)
4. Borderline leprosy (BL)
 Borderline tuberculoid leprosy (BT)
 Borderline borderline leprosy (BB)
 Borderline lepromatous leprosy (BL)

14. Clinical features
1. Skin lesions, usually anaesthetic
 Hypopigmented or erythematus patch / plaque .
2. Complete / partial loss of sensation.
 Painless wounds or burns on the hands or feet
 Paresthesias: tingling or numbness in the hands or feet
 Diminished sensation or loss of sensation within skin patch(es)
3. Thickening of peripheral nerves.
4. Lumps or swelling on the earlobes or face.
5. Tender, enlarged peripheral nerves.

15. Indeterminate leprosy :Hypopigmented patch, sensation normal, no
palpable peripheral nerve and slit skin smear negative

16. Tuberculoid Leprosy: Annular, erythematous, anasthetic patch with well
defined and raised borders and SSS Negative.

17. Tuberculoid leprosy: Two hypopigmented patches, hypoasthetic well
defined borders, palpable peripheral nerve and SSS negative.

20. Borderline lepromatous leprosy (BL/MB)
Borderline lepromatous case showing borderline tuberculoid and
"punched- out" mid borderline lesions together with papular and
nodular lesions more typical of lepromatous disease.

21. A -Claw hand due to median and ulnar
nerve damage.
B- hands showing neurotrophic
atrophy.

22. Objectives
• Definition.
• Overview.
• Modes of transmission
• Risk factors.
• Clinical features.
• Types/classifications.
• Diagnosis
• Pathogenesis
• Treatment.
• Complications.
• Epidemiology & preventions.

23. Pathogenesis
• The areas most commonly affected by leprosy
are the superficial peripheral nerves , skin
,mucous membranes of the upper respiratory
tract, eyes , and tests
• Tissue damage is caused by the degree to which
cell-mediated immunity is expressed , the extent
of bacillary spread and multiplication ,
immunologic complication and nerve damage

24. Cont…
• M leprae is an obligate intracellular acid-fast
bacillus with unique ability to enter nerves

25. Diagnosis
• Diagnosis of leprosy is most commonly based
on the clinical sign and symptoms.
• In an endemic country or area, an individual
should be regarded as having leprosy if he or
she shows ONE of the following cardinal signs :
• skin lesion consistent with leprosy and with
definite sensory loss, with or without thickened
nerves
• positive skin smears

26. Cont…
• If you have a suspicious skin sore, your doctor
will remove a small sample of the abnormal skin
and send it to a laboratory to be examined. This
is called a skin biopsy . A skin smear test may
also be done. With paucibacillary leprosy, no
bacteria will be detected. In contrast, bacteria are
expected to be found on a skin smear test from a
person with multibacillary leprosy.

28. Treatment
• Common drugs
i. Dapson
ii. Refampicine
iii. Clofazimine
The combination of these three drugs
Is known as multi drug therapy (MDT)

29. Cont…
• 6 month regimen for Paucibacillary (PB)
Leprosy
oDapson 100 mg (daily)
oRefampicin 600 mg (monthly)

30. Cont…
• 12 month regimen for Multibacillary
(MB) Leprosy
oDapsone 100 mg (daily)
oRefampicin 600 mg (monthly)
oClofazimine 300 mg (monthly) or
o50 mg (daily)

31. complication
• disfigurement
• hair loss, particularly on the eyebrows and eyelashes
• muscle weakness
• permanent nerve damage in the arms and legs
• inability to use the hands and feet
• Nosebleeds
• iritis (inflammation of the iris of the eye), glaucoma
(an eye disease that causes damage to the optic
nerve), and blindness
• Infertility
• kidney failure

33. References
• WHO.
• UPTODATE.
• Kumar & Clarks clinical medicine.