Hansen's disease, also known as leprosy, is a chronic infection caused by Mycobacterium leprae. It primarily affects the skin, nerves, eyes, and mucous membranes. It is transmitted through droplets from the nose and mouth during close, repeated contact with untreated cases. Symptoms vary depending on the type of leprosy, which is classified by Ridley-Jopling scale ranging from tuberculoid to lepromatous forms. Diagnosis involves examination of skin lesions, sensory and motor impairment, and identification of acid-fast bacilli in smears. Differential diagnosis includes other causes of skin lesions and peripheral neuropathy.

1. Hansen’s Disease

2. History
 Definition: Leprosy is a chronic systemic disease
caused by Mycobacterium leprae manifesting as
development of specific granulomatous or
neurotrophic lesions in the skin, mucous membrane,
eyes nerves, bones and viscera.
 Oldest infection known to mankind
 Synonyms: Hansen’s disease, ‘Kushtha roga’

3. Transmission of Leprosy
 Respiratory route: inhalation of bacilli-laden
droplets
 Cutaneous: skin to skin contact
 GIT : ingestion of food
 Intradermal : inoculation by tattoos
} Not
Yet
Proven

4. Epidemiological factors
 Occurs at all age groups
 Peak age of onset : Between 10 – 20 years
 Males > Females
 Children most susceptible
 Immune status ( host resistance)
 Overcrowding
 Low socioeconomic status

5. Immunity and Leprosy
Host resistance
 Excellent
 Good
 Fair
 Poor
 Very poor
Clinical manifestation
No infection
Subclinical infection with
spontaneous regression
Indeterminate, pure neuritic,
tuberculoid
Mid-borderline,
borderline-lepromatous
Lepromatous

6. Mycobacterium Leprae
 Obligate, intracellular, acid-fast bacillus
 Affinity for skin, nerves and muscle tissue
 Found in macrophages, histiocytes and Schwann
cells.
 Non cultivable
 Grown in animal models
 Closely resembles M.tuberculosis, but less acid-fast.
 Multiplies in 11-13 days.

7. Classification
The Ridley Jopling classification
 Indeterminate
 Tuberculoid
 Borderline: borderline-tuberculoid,
mid-borderline,
borderline-lepromatous
 Lepromatous
Pure neural, Maculoanaesthetic - Indian classification

8. Classification
 Paucibacillary Leprosy(PB):
Indeterminate leprosy (I)
Tuberculoid leprosy (TT)
Borderline tuberculoid (BT)
Pure neuritic (PN)*
 Multibacillary Leprosy(MB):
Midborderline leprosy (BB)
Borderline lepromatous (BL)
Lepromatous leprosy (LL)
* Asymmetric nerve involvement with no skin lesion
and usually of tuberculoid origin.

9. Tuberculoid (TT)
 Single or few, asymmetrical, well-defined,
erythematous or copper-coloured patches
 Sensations - Absent
 Nerves - thickened, presence of feeding nerves,
abscesses
 Skin smears - Negative
 Lepromin test - Strongly positive
 Course - Relative benign and stable, with good
prognosis.

10. Borderline leprosy
Common type of leprosy
 Subdivided into BT, BB & BL.
 Course - Unstable with variable prognosis , may
progress to sub-polar LL leprosy.
 Most prone to reactions.
 Lepromin test -Negative ,weakly positive in BT.

11. Borderline Tuberculoid (BT)
 Few asymmetric, hypopigmented or skin coloured
macules, plaques with ill defined margins
 Presence of satellite lesion near the advancing
margin of patch
 Sensory impairment - Marked
 Nerve involvement - Marked and asymmetrical

12. Midborderline leprosy (BB)
 Unstable form, reactions frequent
 Annular lesions with characteristic punched out
appearance (inverted saucer shaped)
 Sensory impairment - Moderate.
 Nerve involvement - Marked and asymmetrical.

13. Borderline lepromatous leprosy (BL)
 Multiple shiny macules, papules, nodules and
plaques with sloping edges
 Sensory impairment - Slight
 Nerve involvement - Widespread and less
asymmetrical.
 Glove & stocking hypoaesthesia

14. Lepromatous leprosy
 Hypopigmented, erythematous or coppery, shiny
macules, papules, nodules
 Lesions symmetrically distributed, small, multiple,
shiny with normal or mild sensory loss
 Leonine facies: Infiltration of skin with nodules, loss
of eyebrows and eyelashes
 Nerve involvement symmetrical; glove & stocking
anaesthesia
 Lepromin test - Negative

15. Indeterminate leprosy
 Asymmetrical, single /multiple hypopigmented, or
faintly erythematous and ill-defined macules.
 Sensation - Normal or slightly impaired
 Peripheral nerves - Normal
 Skin smears - Negative
 Lepromin test - Unpredictable and variable
 Course - Usually self limiting ,may progress to other
forms of leprosy.

16. Pure Neuritic leprosy
 Neuritic manifestations -Tingling, heaviness and
numbness, paresis, hypotonia, atrophy, claw hand
and toes, wrist-drop, foot-drop.
No skin lesion.
 Other changes-Anhidrotic, dry glossy skin, blisters,
neuropathic ulcers, decalcification, bone
resorption.

17. Pure Neuritic leprosy
 Lepromin test -Slightly positive.
 Course-Spontaneous regression or progression to
TT leprosy.
 Silent neuritis (silent neuropathy)
Sensory or motor impairment without skin signs of
reversal reaction or ENL ,tenderness, paraesthesiae
or numbness.

18. Special forms of Leprosy
 Lucio Leprosy:
Rare form of lepromatous leprosy, described in
Mexico. Diffuse widespread infiltration of skin, loss
of body hair, loss of eyebrows & eyelashes, and
widespread sensory loss.
 ‘Lepra Bonita’ (Pretty leprosy)
Elderly persons with diffuse infiltration of face
smoothes out wrinkles, giving youthful appearance.
 Histoid leprosy:
BL patients with irregular or poor treatment
compliance
Drug resistant cases

19. Eye Involvement in Leprosy
 Lagophthalmos (partial/complete,
unilateral/bilateral)
 Conjunctivitis
 Exposure keratitis and corneal ulcers
 Madarosis, trichiasis leading to corneal vascularity
and opacity
 Dacryocystitis (acute,subacute or chronic)
 Nodules on sclera, episcleritis, scleritis
 Corneal nodules and lepromatous pearls
 Microlepromata, nodules on iris and ciliary body

20. Nerve Involvement in Leprosy
 Sensory involvement - Anaesthesia in hands & feet,
glove and stocking anaesthesia, repeated trauma
 Motor involvement- Wasting and paralysis of
muscles
 Autonomic involvement -Icthyosis, loss of hair and
sweating.

21. Other features
 Nasal stuffiness / crusting
 Epistaxis
 Hoarseness of voice
 Gynaecomastia
 Saddle nose
 Bone resorption
 Lymphadenopathy

22. Differential diagnosis of leprosy
Macular lesions
 Vitiligo
 Occupational leucoderma
 Tinea versicolor
 Pityriasis alba
 Post kala azar dermal leishmaniasis
 Naevus depigmentosus
 Scars

23. Differential diagnosis of leprosy
Infiltrated lesions
 Lupus vulgaris
 Lupus erythematosus
 Granuloma annulare
 Annular syphilides
 Post kala azar dermal leismaniasis (infiltrated
lesions)
 Sarcoidosis
 Psoriasis

24. Differential diagnosis of leprosy
Nodular lesions
 Post kala azar dermal leismaniasis
 Cutaneous leismaniasis
 Syphilis
 Onchocerciasis
 Sarcoidosis
 Leukaemia cutis
 Mycosis Fungoides
 Nodules of neruofibromatosis

25. Differential diagnosis of neurological conditions
Sensory impairment with or without muscle wasting
 Peripheral neuropathy
 Diabetic neuropathy
 Primary amyloidosis of peripheral nerves
 Congential sensory neuropathy
 Syringomyelia
 Tabes dorsalis
 Thoracic outlet syndrome
 Alcoholic neuropathy

26. Diagnosis
Cardinal signs of leprosy
 Sensory impairment in affected areas
 Enlargement of peripheral nerves associated with
signs of peripheral nerve damage
 Finding acid-fast bacilli in the lesions

27. Clinical examination
 Type and number of skin lesions
 Sensory impairment
 Motor examination
 Nerve examination
 Sweating
 Loss of hair

28. Clinical examination: Sensory
 Touch
Tested with wisp of cotton,nylon thread or feather.
 Temperature
Tested with two test tubes – one containing hot water
and other cold
 Pain
Tested by pin prick

29. Clinical examination : Motor
 Testing of motor power- Done clinically
 Electro-diagnosis - Employed in very early cases.
Electrical stimulator using faradic and galvanic
current used to test muscle power.

30. Nerves
 Supra/ infraorbital
 Greater auricular
 Clavicular
 Radial
 Sup. Radial cut
 Ulnar
 Median
 Lateral popliteal
 Posterior tibial
 Anterior tibial
 Sural