LEPROSY
Diagnosing leprosy
Although skin patches are often the first sign of leprosy, many other diseases can
cause similar patches. Only when there is a loss of feeling inside the skin patch, as
compared with the skin outside the patch, can we be almost sure the person has
leprosy. However, in some forms of leprosy, loss of feeling in skin patches may develop
only years later, or not at all. Therefore, other evidence of leprosy must be looked for.
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Another sign of leprosy—tingling, numbness, or loss of feeling in hands and feet—
may also have other causes.
To make a fairly certain diagnosis of leprosy, the person should have at least 1 of
these 3 major signs:
1. definite loss or change of
feeling in skin patches
Note: Leprosy patches
on face often do not lose
feeling as much as on
other parts of the body.
2. definite enlargement of nerves
(For nerves to check, see p. 216.)
3. presence of leprosy bacilli in a ‘skin smear’
A ‘split skin smear’ is prepared by cutting a thin layer
of skin from a skin patch. Less commonly it is taken
from the moist skin deep inside the nose—an area
that is often heavily infected. The skin sample is
placed on a glass slide, colored with special stains,
and examined with a microscope.
The bacteria (bacilli) of leprosy, if present,
can be seen under the microscope.
taking a
‘split skin
smear’ from
a skin patch
leprosy
bacilli as
seen in the
microscope
Whenever you suspect leprosy but the diagnosis is uncertain,
a ‘skin smear’ should be taken (by a trained worker).
Note: Not many persons with leprosy show all 3 of these signs. Persons with loss of
feeling in skin patches usually have no bacilli in their skin smears.
disabled village children