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Scabies
S cabies is a cutan eous p arasitosis d ue to th e p resen ce of th e m ite Sarcoptes scabiei
hominis w ithin the ep id erm is. I t exists in tw o form s: ord in ary scabies, relatively ben ign
an d m od erately con tagious; an d crusted scabies, favoured by im m un e d eficien cy,
extrem ely con tagious an d refractory to con ven tion al treatm en t. P erson to p erson
tran sm ission tak es p lace chiefly through d irect sk in con tact, an d som etim es by in d irect
con tact ( sh arin g cloth in g, bed d in g) . T h e ch allen ge in m an agem en t is th at it m ust
in clud e sim ultan eous treatm en t of both the p atien t an d close con tacts, an d at the sam e
tim e, d econ tam in ation of clothin g an d bed d in g of all p erson s un d ergoin g treatm en t, in
ord er to break the tran sm ission cycle.
Clinical features
Ordinary scabies
In older children and adults
– I tch in g, w orse at n ight, very suggestive of scabies if close con tacts have the sam e
sym p tom
an d
– T yp ical sk in lesion s:
•S cabies burrow s (com m on ): fin e w avy lin es of 5 to 1 5 m m , corresp on d in g to the
tun n els m ad e by the p arasite w ithin the sk in . B urrow s are m ost often seen in the
in terd igital sp aces of the han d an d flexor asp ect of the w rist, but m ay be p resen t on
the areolae, buttock s, elbow s, axillae. T he back an d the face are sp ared . B urrow s
m ay be associated w ith vesicles, corresp on d in g to the en try p oin t of the p arasite in
the sk in .
•S cabies n od ules (less com m on ): red d ish-brow n n od ules, m easurin g 2 to 2 0 m m , on
th e gen itals in m en , p ersistin g after effective treatm en t ( th ey are n ot n ecessarily
in d icative of active in fection ).
an d / or
– S econ d ary sk in lesion s: resultin g from scratch in g ( excoriation s, crusts) or sup er-
in fection (im p etigo).
T yp ical lesion s an d secon d ary lesion s m ay co-exist, or sp ecific lesion s m ay be en tirely
m ask ed by secon d ary lesion s.
In infants and young children
– V esicular erup tion ; often in volvin g p alm s an d soles, back , face, an d lim bs. S econ d ary
in fection or ecz em atisation is freq uen t. Isolated scabies n od ules in the axillae m ay be
the on ly m an ifestation .
– E xam in ation of the m other‟s han d s m ay sup p ort the d iagn osis.
Crusted (Norwegian) scabies
T hick , scaly, erythem atous p laq ues, gen eralised or localised , resem blin g p soriasis, w ith
or w ithout itchin g (5 0 % of cases). D elay in d iagn osis m ay lead to a scabies ep id em ic.
98
Scabies
S cabies is a cutan eous p arasitosis d ue to th e p resen ce of th e m ite Sarcoptes scabiei
hominis w ithin the ep id erm is. I t exists in tw o form s: ord in ary scabies, relatively ben ign
an d m od erately con tagious; an d crusted scabies, favoured by im m un e d eficien cy,
extrem ely con tagious an d refractory to con ven tion al treatm en t. P erson to p erson
tran sm ission tak es p lace chiefly through d irect sk in con tact, an d som etim es by in d irect
con tact ( sh arin g cloth in g, bed d in g) . T h e ch allen ge in m an agem en t is th at it m ust
in clud e sim ultan eous treatm en t of both the p atien t an d close con tacts, an d at the sam e
tim e, d econ tam in ation of clothin g an d bed d in g of all p erson s un d ergoin g treatm en t, in
ord er to break the tran sm ission cycle.
Clinical features
Ordinary scabies
In older children and adults
– I tch in g, w orse at n ight, very suggestive of scabies if close con tacts have the sam e
sym p tom
an d
– T yp ical sk in lesion s:
•S cabies burrow s (com m on ): fin e w avy lin es of 5 to 1 5 m m , corresp on d in g to the
tun n els m ad e by the p arasite w ithin the sk in . B urrow s are m ost often seen in the
in terd igital sp aces of the han d an d flexor asp ect of the w rist, but m ay be p resen t on
the areolae, buttock s, elbow s, axillae. T he back an d the face are sp ared . B urrow s
m ay be associated w ith vesicles, corresp on d in g to the en try p oin t of the p arasite in
the sk in .
•S cabies n od ules (less com m on ): red d ish-brow n n od ules, m easurin g 2 to 2 0 m m , on
th e gen itals in m en , p ersistin g after effective treatm en t ( th ey are n ot n ecessarily
in d icative of active in fection ).
an d / or
– S econ d ary sk in lesion s: resultin g from scratch in g ( excoriation s, crusts) or sup er-
in fection (im p etigo).
T yp ical lesion s an d secon d ary lesion s m ay co-exist, or sp ecific lesion s m ay be en tirely
m ask ed by secon d ary lesion s.
In infants and young children
– V esicular erup tion ; often in volvin g p alm s an d soles, back , face, an d lim bs. S econ d ary
in fection or ecz em atisation is freq uen t. Isolated scabies n od ules in the axillae m ay be
the on ly m an ifestation .
– E xam in ation of the m other‟s han d s m ay sup p ort the d iagn osis.
Crusted (Norwegian) scabies
T hick , scaly, erythem atous p laq ues, gen eralised or localised , resem blin g p soriasis, w ith
or w ithout itchin g (5 0 % of cases). D elay in d iagn osis m ay lead to a scabies ep id em ic.
98
