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4. Skin diseases
Leprosy (Hansen‟s disease)
A n en d em ic, chron ic bacterial in fection d ue to Mycobacterium leprae. H um an s are th e
on ly reservoir of p roven sign ifican ce. L ep rosy is n ot very con tagious w ith tran sm ission
through p rolon ged , close, d irect con tact, p articularly betw een h ouseh old m em bers.
C hild ren are m ost at risk of con tractin g the d isease.
Clinical features
L ep rosy should be con sid ered in an y p atien t p resen tin g w ith hyp op igm en ted sk in
lesion s
or p erip heral n europ athy. In susp ect cases, con d uct a thorough clin ical exam in ation : 4
– sk in an d m ucous m em bran es (p atien t m ust be un d ressed )
– n eurological exam in ation : sen sitivity to light touch, p in p rick an d tem p erature (hot-
cold test)
– p alp ation of the p erip heral n erves
D ifferen t clin ical form s an d classification of lep rosy exist.
T h e R id ley- J op lin g classification d ifferen tiates 5 form s based on several factors,
in clud in g the bacteriological in d ex.
T he W H O clin ical classification is sim p lified to in clud e on ly 3 form s (see n ext p age)
The Ridley-Jopling classification of leprosy
Paucibacillary forms Multibacillary forms
(least con tagious form s) (m ost con tagious form s)
T uberculoid B ord erlin e B ord erlin e B ord erlin e L ep rom atous
T uberculoid L ep rom atous
T .T . B .T . B .B . B .L . L .L .
Tuberculoid leprosy
– T he p rim ary characteristic is p erip heral n erve in volvem en t: ten d er, in filtrated an d
thick en ed n erves; loss of therm al, then tactile an d p ain sen sation . T his m ay lead to
trop hic ulcers an d m utilation s of the extrem ities.
– L esion s are sin gle or few in n um ber:
•p laq ue w ith a w ell-d em arcated raised bord er an d an atrop hic, clear cen tre
or
•erythem atous m acule on p ale sk in , hyp op igm en ted m acule on d ark sk in
– N erve in volvem en t d evelop s late in the d isease.
Lepromatous leprosy
– T he p rim ary characteristic is m ultip le m uco-cutan eous lesion s:
•m acules, p ap ules or in filtrated n od ules on the face, ear lobes an d the up p er an d
low er lim bs. L esion s are bilateral, sym m etrical, p igm en ted . I n itially, th ere is n o
sen sory loss.
•in volvem en t of the n asal m ucosa w ith crustin g an d n ose bleed s
•oed em a of the low er lim bs
– N erve in volvem en t d evelop s late in the d isease.
113
Leprosy (Hansen‟s disease)
A n en d em ic, chron ic bacterial in fection d ue to Mycobacterium leprae. H um an s are th e
on ly reservoir of p roven sign ifican ce. L ep rosy is n ot very con tagious w ith tran sm ission
through p rolon ged , close, d irect con tact, p articularly betw een h ouseh old m em bers.
C hild ren are m ost at risk of con tractin g the d isease.
Clinical features
L ep rosy should be con sid ered in an y p atien t p resen tin g w ith hyp op igm en ted sk in
lesion s
or p erip heral n europ athy. In susp ect cases, con d uct a thorough clin ical exam in ation : 4
– sk in an d m ucous m em bran es (p atien t m ust be un d ressed )
– n eurological exam in ation : sen sitivity to light touch, p in p rick an d tem p erature (hot-
cold test)
– p alp ation of the p erip heral n erves
D ifferen t clin ical form s an d classification of lep rosy exist.
T h e R id ley- J op lin g classification d ifferen tiates 5 form s based on several factors,
in clud in g the bacteriological in d ex.
T he W H O clin ical classification is sim p lified to in clud e on ly 3 form s (see n ext p age)
The Ridley-Jopling classification of leprosy
Paucibacillary forms Multibacillary forms
(least con tagious form s) (m ost con tagious form s)
T uberculoid B ord erlin e B ord erlin e B ord erlin e L ep rom atous
T uberculoid L ep rom atous
T .T . B .T . B .B . B .L . L .L .
Tuberculoid leprosy
– T he p rim ary characteristic is p erip heral n erve in volvem en t: ten d er, in filtrated an d
thick en ed n erves; loss of therm al, then tactile an d p ain sen sation . T his m ay lead to
trop hic ulcers an d m utilation s of the extrem ities.
– L esion s are sin gle or few in n um ber:
•p laq ue w ith a w ell-d em arcated raised bord er an d an atrop hic, clear cen tre
or
•erythem atous m acule on p ale sk in , hyp op igm en ted m acule on d ark sk in
– N erve in volvem en t d evelop s late in the d isease.
Lepromatous leprosy
– T he p rim ary characteristic is m ultip le m uco-cutan eous lesion s:
•m acules, p ap ules or in filtrated n od ules on the face, ear lobes an d the up p er an d
low er lim bs. L esion s are bilateral, sym m etrical, p igm en ted . I n itially, th ere is n o
sen sory loss.
•in volvem en t of the n asal m ucosa w ith crustin g an d n ose bleed s
•oed em a of the low er lim bs
– N erve in volvem en t d evelop s late in the d isease.
113
