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ariasis
often superinfected ( « filarial scabies ») 1. T h is arises from d erm al inv asion by
m icrofilariae.
– L ate ch ronic skin lesions: patch y d epig m entation on th e sh ins (« leopard skin »), skin
atroph y or areas of d ry, th ickened , peeling skin (lich enification; “lizard skin”).
– V isual d isturbances and ocular lesions: see pag e 1 2 8 .
Laboratory
– D etection of th e m icrofilariae in th e skin (skin snip biopsy, iliac crest).
– If th e skin biopsy is positiv e, look for loiasis in reg ions w h ere loiasis is co-end em ic
(m ainly in C entral A frica).
Treatment
Antiparasitic treatment
– D ieth ylcarbam azine is contra-ind icated (risk of sev ere ocular lesions).
– Doxycycline P O ( 2 0 0 m g / d ay for 4 w eeks; if possible 6 w eeks) kills a sig nificant
percentag e of ad ult w orm s and prog ressiv ely red uces th e num ber of O. volvulus
m icrofilariae2 . I t is contra- ind icated in ch ild ren < 8 years and preg nant or breast-
feed ing w om en.
– Ivermectin P O is th e d rug of ch oice: 1 5 0 m icrog ram s/ kg as a sing lendd ose; a 2 d ose
sh ould be ad m inistered after 3 m onth s if clinical sig ns persist. R epeat th e treatm ent
ev ery 6 or 1 2 m onth s to m aintain th e parasite load below th e th resh old at w h ich
clinical sig ns appea3r . I v erm ectin is not recom m end ed in ch ild ren < 5 years or < 1 5 kg
and preg nant w om en.
– I n case of co- infection w ith Loa loa or in reg ions w h ere loiasis is co- end em ic,
iv erm ectin sh ould be ad m inistered w ith caution (risk of sev ere ad v erse reactions in
patients w ith h ig h L. loa m icrofilarial load ):
• If it is possible to test for Loa loa (th ick blood film ):
C onfirm and quantify th e m icrofilaraem ia. A d m inister th e appropriate treatm ent
accord ing to th e m icrofilarial load (see Loiasis, pag e 1 5 9 ).
• I f it is not possible to perform a th ick film exam ination, take a h istory from th e
patient:
I f th e patient h as receiv ed a prev ious treatm ent w ith iv erm ectin w ith out
d ev eloping serious ad v erse reactions (see pag e 1 6 0 ), ad m inister th e treatm ent.
I f th e patient h as nev er receiv ed iv erm ectin nor d ev eloped sig ns of loiasis
( m ig ration of an ad ult w orm und er th e conjunctiv a, or « C alabar » sw elling s) ,
ad m inister th e treatm ent.
I f th e patient alread y h as d ev eloped sig ns of loiaisis and if onch ocerciasis h as a
sig nificant clinical im pact, ad m inister iv erm ectin und er close superv ision ( see
Loiasis, pag e 1 5 9 ) or use an alternativ e (d oxycycline, as abov e).
– I n th e case of concom itant lym ph atic filariasis: ad m inister iv erm ectin first th en start
treatm ent for lym ph atic filariasis w ith d oxycycline P O ( see pag e 1 6 2 ) one w eek
later.
1 Differential diagnosis is sarcoptic scabies (page 98).
2 Elimination of Wolbachia reduces the longevity and fertility of the macrofilariae, and thus the production of new
microfilariae within the organism.
3 Ivermectin kills microfilariae and disrupts production of microfilariae by adult worms. However the treatment
must be administered at regular intervals since it does not kill adult worms.
158
often superinfected ( « filarial scabies ») 1. T h is arises from d erm al inv asion by
m icrofilariae.
– L ate ch ronic skin lesions: patch y d epig m entation on th e sh ins (« leopard skin »), skin
atroph y or areas of d ry, th ickened , peeling skin (lich enification; “lizard skin”).
– V isual d isturbances and ocular lesions: see pag e 1 2 8 .
Laboratory
– D etection of th e m icrofilariae in th e skin (skin snip biopsy, iliac crest).
– If th e skin biopsy is positiv e, look for loiasis in reg ions w h ere loiasis is co-end em ic
(m ainly in C entral A frica).
Treatment
Antiparasitic treatment
– D ieth ylcarbam azine is contra-ind icated (risk of sev ere ocular lesions).
– Doxycycline P O ( 2 0 0 m g / d ay for 4 w eeks; if possible 6 w eeks) kills a sig nificant
percentag e of ad ult w orm s and prog ressiv ely red uces th e num ber of O. volvulus
m icrofilariae2 . I t is contra- ind icated in ch ild ren < 8 years and preg nant or breast-
feed ing w om en.
– Ivermectin P O is th e d rug of ch oice: 1 5 0 m icrog ram s/ kg as a sing lendd ose; a 2 d ose
sh ould be ad m inistered after 3 m onth s if clinical sig ns persist. R epeat th e treatm ent
ev ery 6 or 1 2 m onth s to m aintain th e parasite load below th e th resh old at w h ich
clinical sig ns appea3r . I v erm ectin is not recom m end ed in ch ild ren < 5 years or < 1 5 kg
and preg nant w om en.
– I n case of co- infection w ith Loa loa or in reg ions w h ere loiasis is co- end em ic,
iv erm ectin sh ould be ad m inistered w ith caution (risk of sev ere ad v erse reactions in
patients w ith h ig h L. loa m icrofilarial load ):
• If it is possible to test for Loa loa (th ick blood film ):
C onfirm and quantify th e m icrofilaraem ia. A d m inister th e appropriate treatm ent
accord ing to th e m icrofilarial load (see Loiasis, pag e 1 5 9 ).
• I f it is not possible to perform a th ick film exam ination, take a h istory from th e
patient:
I f th e patient h as receiv ed a prev ious treatm ent w ith iv erm ectin w ith out
d ev eloping serious ad v erse reactions (see pag e 1 6 0 ), ad m inister th e treatm ent.
I f th e patient h as nev er receiv ed iv erm ectin nor d ev eloped sig ns of loiasis
( m ig ration of an ad ult w orm und er th e conjunctiv a, or « C alabar » sw elling s) ,
ad m inister th e treatm ent.
I f th e patient alread y h as d ev eloped sig ns of loiaisis and if onch ocerciasis h as a
sig nificant clinical im pact, ad m inister iv erm ectin und er close superv ision ( see
Loiasis, pag e 1 5 9 ) or use an alternativ e (d oxycycline, as abov e).
– I n th e case of concom itant lym ph atic filariasis: ad m inister iv erm ectin first th en start
treatm ent for lym ph atic filariasis w ith d oxycycline P O ( see pag e 1 6 2 ) one w eek
later.
1 Differential diagnosis is sarcoptic scabies (page 98).
2 Elimination of Wolbachia reduces the longevity and fertility of the macrofilariae, and thus the production of new
microfilariae within the organism.
3 Ivermectin kills microfilariae and disrupts production of microfilariae by adult worms. However the treatment
must be administered at regular intervals since it does not kill adult worms.
158
