Leprosy is a chronic
systemic bacterial infection caused by mycobacterium leprae .
Predisposing
factors
Modes
of Infections
-
Direct contact with
the infected individuals.
-
Person to person
infection.
-
Contact with infected
ulcerating lesions .
-
Secretions of
infected mucous membranes.
-
Insects such as
cockroaches , bed bugs and skin parasites .
Clinical
types
-
Lepromatous leprosy
-
Tuberculoid leprosy
-
Borderline leprosy
LEPROMATOUS
LEPROSY
The diagnosis of leprosy
is vague until the diagnostic skin lesions begin to appear or after the
characteristic features become manifested .
Prodromal
manifestations
The secondary lesion
begins by non-specific manifestations such as fever , muscle pain and
numbness .
Skin
manifestations:
Skin lesions are macules
followed later by anesthesia , paralysis and trophic changes . This type
is contagious where the bacilli are abundant in the nodules and secretions
of the infected mucous membranes .
The early skin
manifestation is usually a solitary hypo-pigmented macule that enlarges
gradually mainly on the cheeks , upper arms , buttocks and thighs.
Sensory
manifestations
The earliest
manifestations are sensory manifestations. Numbness and inability to
differentiate cold and heat sensations .
The lepromin test is
negative .
Clinical
types of lepromatous leprosy
-
Macular type :
The lesions are:
-
Diffuse, ill-defined,
shiny, greasy macules .
-
Symmetrically
distributed.
-
Sensory sensations
are not changed .
-
Skin over the macules
is almost normal .
-
Hair changes:
progressive hair fall of the eyebrows, or eyelashes. Scalp hair is not
affected .
-
Lepromatous
infiltration
The skin lesions may be diffuse, plaque or nodular.
-
Diffuse type
Diffuse lepromas are shiny, waxy infiltrating nodules with an
erythematous, cyanotic surface due to fusion of the macules. The main
areas involved are the face, mainly the forehead. The infiltrate is
ill-defined nodules slightly anesthetic and devoid of hair mainly on
the supra-orbital area, forehead, face, ears, hands and buttocks.
Hair changes are loss of the eyebrow hair.
Disfiguration giving the leonine appearance (lion faces ).
Course
of the infiltrate:
May involute
spontaneously.
Increases in size forming large plaques .
Diffuse leprosy of Lucio : is uncommon type of the diffuse leprosy .
The lesions show multiple necrosis and ulceration that heal by
extensive scarring.
-
Ulcerating type :
The ulcer is indolent, covered by seropurulent exudate and
characteristically heals with scarring, causing destruction and
deformities of the affected areas.
-
Lichen leprosus
This type has a very chronic course. The lesions become stable without
changes for a long time .
Skin lesion is yellowish, small, follicular hard papules with sharp
boundaries giving the "goose skin" appearance .
-
Neural involvement
All patients with lepromatous leprosy manifest with varying degree of
nerve involvement such as anesthesia, nerve enlargement, trophic
changes muscular atrophy, paralysis and wasting .
Sensory
changes
-
Inability to
differentiate heat from cold sensations . These may be the first signs
of the lepromatous leprosy .
-
Touch sensation
impairment .
-
Anesthesia .
-
Loss of pain
sensation.
-
Numbness, burning and
tingling sensation of the affected parts of the feet, hands, legs and
the back .
-
Trophic ulcers of the
feet .
-
Eye manifestations of
lepromatous leprosy
-
Mucous membrane
manifestations
Nose : nodules and infiltration with ulceration of the nasal septum
leading to saddle nose shape
Vocal cord : hoarseness of the voice .
-
Teeth - loss of the
upper incisor teeth.
-
Internal organs
manifestations
Liver , spleen , bone
marrow, testicles, lymph nodes and reticulo-endothelial system may be
involved .
TUBERCULOID
LEPROSY
This is less serious type
where lepra bacilli are few or even absent in the lesions. Lepromin test
is positive.
Nerve involvement is more
than skin involvement causing anesthesia and thickened nerves.
Tuberculoid leprosy has
usually good prognosis .
Clinical
features
Childhood
leprosy
The lesions appear as
solitary , raised erythematous macule or a group of tiny papule surrounded
by hypopigmented halo mainly on the exposed skin surface . The lesion
usually passes without notice and disappears after one or two
years-leaving hypopigmented thin scar .
Adulthood
Leprosy
Infection erupts later
on, after a very long period of quiescence until puberty.
Skin manifestations:
Skin lesion appears as
large , erythematous plaque , with sharp , ill-defined and elevated border
and atrophic center forming arciform , annular and circinate plaques on
healing. The bacilli are less abundant than that of the lepromatous type .
The area above the skin
lesions is dry ,scaly, thick , rough and has the appearance of pigskin.
Anesthesia of the lesions
which are accompanied by hypopigmented, hypohidrotic maculo-anaesthetic
manifestations mainly on the face and limbs.
Healing of the lesions
leave scarring and pigmentary changes .
Neural manifestations:
Nerve involvement may
lead to:
Nerve enlargement and
thickening.
Anesthesia
Muscular paralysis
, wasting and atrophy .
BORDERLINE
TUBERCULOID
The lesions are the same
as tuberculoid but smaller and more numerous. Lepra bacilli do not exist
in this type or may be very rare. This type is usually non-contagious .
Systemic manifestations
such as neural and hair involvement are minimal.
BORDERLINE
LEPROSY
The lesions are few,
asymmetrical and consist of vague irregular shaped plaques with
ill-defined borders. Small satellite lesions may develop.
In this type the skin and
nerves are the only affected . Anesthesia is usually moderate .
Clinical
features
The lesions of borderline
lepromatous type are sparse , which may be macular, papular, or plaques .
Absence of lepromatous
features such as keratitis, ulceration and disfiguration.
Nerve involvement may
occur later .
INDETERMINATE
LEPROSY
Skin manifestations are
macules followed later by anesthetic and trophic lesions. Plaques and
nodules do not occur in this type .
Histopathology
of leprosy
The infected tissues show
chronic inflammatory infiltrate in a banal shape around the blood vessels,
nerves, and glands of the skin with small round cells and occasionally
histiocytes and fibroblasts. The histopathological changes depend on the
type of leprosy.
-
Lepromatous
type
The granulomatous lesions are
composed chiefly of bacillus-laden histiocytes (foam cells).
Atrophy of the epidermis and sweat glands .
Acid-fast bacilli are profuse in the section .
-
Tuberculoid
leprosy
This type shows high degree
of resistence
-
The follicular type:
shows tuberculoid granuloma in the epidermis composed of epitheloid
cells and some giant cells .
-
The sarcoid variety :
presents with granuloma, which is formed of epitheloid cells and
lymphocytes.
-
Borderline
tuberculoid
The histological picture is
mainly histiocytes with few epitheloid cells and dense lymphocytes
infiltration.
Few bacilli and some vacuolated cells may be seen in the field.
-
Borderline
lepromatous leprosy
Diffuse spread of epitheloid
cells through the granuloma.
Abundant lepra bacilli.
Lymphocytes are not aggregated in zones .
Absent giant cells .
Differential
Diagnosis of Leprosy
Some authors describe
leprosy as "the great imitators" that can give clinical picture
simulating different skin diseases .
-
Lepromatous type:
-
Tuberculoid type
-
Borderline
tuberculoid
-
Pityriasis alba
-
Tinea versicolor
-
Seborrheic dermatitis
-
Berloque dermatitis
-
Pellagra
Lepromin test
(Mistuda reaction )
This is an immunologic
test indicating the host resistance to M. leprae .
Lepra
reaction
During treatment of
leprosy two reactions may occur. The cause of these reactions is related
to bacterial products released by disintegration of the bacilli as a
result of the bactericidal action of the sulphones or due to development
of immunity.
The reaction may be :
-
Acute exacerbation
of the lesions - occurs usually during the first four months of
treatment showing swelling and erythema of the existing lesions.
-
Erythema nodosum
leprosum - this is considered an allergic vasculitis that appears
later usually after six months of beginning the treatment .
Clinical
features of Erythema Nodosum
Skin
Manifestations
Small , erythematous
nodules appear in crops, which may be accompanied by systemic
manifestations.
General
Manifestations
Fever, chills, malaise,
muscle pain and arthralgia .
Visceral manifestations:
Nephritis , orchitis and
hepatosplenomegaly
Treatment
of leprosy
-
Dapsone or DDS
(diaminodiphenyl sulphones) is the drug of choice for treatment of all
forms of leprosy.
DOSE : |
|
First 2 weeks : |
25mg
twice a week |
Second 2 weeks: |
50mg
twice a week |
Third 2 weeks: |
75mg
twice a week |
Fourth 2 weeks:
|
100 mg
twice a week.
|
-
Ciba SU-1906
(Diphenyl thiourea) : Adult dose is two-grams daily for two years.
This drug may be useful for cases resistant to sulphones .
-
Madribon
(Sulfadimethoxine): is effective for treatment of tuberculoid leprosy.
-
Lamprene
(Geigy) is useful in treating cases of reactive leprosy. There is less
lepra reaction with this medication and is also used for
sulphones-resistant cases.
Treatment
of Lepra Reaction
Mild
cases:
-
Reduce the dose to
half .
-
Antihistamines
-
Antimalarial drugs
-
If the reaction
persists after all these measures , stop Dapsone.
Moderate
or severe lepra reaction :
-
Stop the medication .
-
Sedatives
-
Antimalarial
-
Antihistamines
-
Steroids
REFERENCES
-
Lara CB. Leprosy in
children: general considerations; initial and early stages. WPR/LEP/24
Geneva: WHO, 1961.
-
Kaplan G, Cohn ZA.
Regulation of cell mediated immunity in lepromatous leprosy. Lepr Rev
1986; 57: 199-207.
-
Neill MA, Hightower
AW, Broome CV. Leprosy in the United States. J Inf Dis 1985; 152:
1064-9.
-
McDougall AC,
Archibald GC. Lepromatous leprosy presenting with swelling of the
legs. Br Med J 1977; i: 23-4.
-
Duncan ME, Melsom R,
Pearson JMH et al. A clinical and immunological Study of four babies
of mothers with lepromatous leprosy, two of whom developed leprosy in
infancy. Int J Lepr 1983; 51: 7-17.
-
Drutz DJ, Chen TSN,
Lu W-H. The continuous bacteraemia of lepromatous leprosy. New Engl J
Med 1972; 287: 159-64.
-
Dabholkar VR,
Gaitonde BB. A study of autonomic functions in leprosy. Leprosy in
India 1982; 54: 303-17.
-
Bryceson ADM,
Pfaltzgraff RF. Leprosy 3rd edn. Edinburgh: Churchill Livingstone,
1990.
-
Pearson JMH. Dapsone
resistant leprosy. Lepr Rev 1983; (Special Issue): 85S-89S.
-
Pedley JC, Harman DJ,
Waudby H et al. Leprosy in peripheral nerves: histopathological
findings in 119 untreated patients in Nepal. J Neurol Neurosurg Psych
1980; 43: 198-204.
-
Ridley DS. Reactions
in leprosy. Lepr Rev 1969; 40: 77-81.
-
Ridley DS, Jopling
WH. Classification of leprosy according to immunity, a five-group
system. Int J Lepr 1966; 34: 255-73.
-
Ellard GA. Rationale
of multidrug regimens recommended by a WHO Study Group on chemotherapy
of leprosy for control programmes. Int J Lepr 1984; 52:394-401.
-
Duncan ME, Melsom R,
Pearson JMH et al. A clinical and immunological Study of four babies
of mothers with lepromatous leprosy, two of whom developed leprosy in
infancy. Int J Lepr 1983; 51: 7-17.
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