8/16/2019 12 - parasitic skin disease.pdf
1/29
Parasitic Skin DiseasesParasitic Skin DiseasesArthropoda:Scabies
Pediculosis
Helminth:
Creeping eruption
(Cutaneous Larva Migrans)
8/16/2019 12 - parasitic skin disease.pdf
2/29
8/16/2019 12 - parasitic skin disease.pdf
3/29
8/16/2019 12 - parasitic skin disease.pdf
4/29
8/16/2019 12 - parasitic skin disease.pdf
5/29
Order : ACARINA
• Family Ixodidae = Hard ticks
• Family Argasidae = Soft ticks
• Family Trombiculidae = Chiggers
• Family Sarcoptidae• Family Demodicidae
• Family Tyroglyphidae
8/16/2019 12 - parasitic skin disease.pdf
6/29
8/16/2019 12 - parasitic skin disease.pdf
7/29
• round, transluscent, dirty white
• six legged larvae
• eight short legged nymphs andadults
Male 0.2 mm
•1st , 2nd legs sucker ended
• 3rd
legs bristle ended• 4th legs sucker ended
Female 0.3-0.4 mm:
• 1st and 2nd legs sucker ended,
• 3rd and 4th legs bristle ended
Order : ACARINA
Family : Sarcoptidae
Species : Sarcoptesscabiei
8/16/2019 12 - parasitic skin disease.pdf
8/29
Mite, feeds on skin and blood
Distribution
• World wide usually associated with:
– unhygienic life-style,
– poor personal hygiene insufficient watersupply
• Wide spread in the tropics, especially chi ldren
Transmission• direct skin contact
• Through bedding and clothing
8/16/2019 12 - parasitic skin disease.pdf
9/29
Mite life cycle
• Eggs Hatch
• 1st instar, nymphs dig into
stratum corneum with
mandibles, moult after 3-4
days
• 2nd instar, protonymphs,
moult after 2-5 days
• 3rd instar, tritonymphs,
moult after 5-6 days
• Adult males and females
• Females moult once more
8/16/2019 12 - parasitic skin disease.pdf
10/29
LIFE CYCLE
• the period from eggs to mature adults takes 10 – 14 days
• both male and female make short burrows in hornysuperficial layer of the skin.
• The gravid female lays her eggs in a burrow.
• The larvae hatch out after 3-4 days, leave the burrow to theskin surface and shelter in the hair follicles.
• After 4-5 days The mites burrow into the upper layer of theskin but never below the stratum corneum. The adult live for4-5 weeks.
• Itch mites are active mainly overnight.
8/16/2019 12 - parasitic skin disease.pdf
11/29
8/16/2019 12 - parasitic skin disease.pdf
12/29
8/16/2019 12 - parasitic skin disease.pdf
13/29
8/16/2019 12 - parasitic skin disease.pdf
14/29
Clinical features:
• The activities and secretions cause
intense itching of affecting area.
• Small vesicles and rash may be seen
on the skin surface.
• Scratching may convert the papule
into pustule (bleeding, secondary
bacterial infection)
Norwegian Scabies => crusted
scabies
• Prefered sites
• axilla, around the waist, inner
aspect of thighs, back of the legs,
interdigital and popliteal folds and
also all over the body
8/16/2019 12 - parasitic skin disease.pdf
15/29
Mites burrowing under theskin cause a rash, which ismost frequently found on:
•hands, particularly thewebbing between the
fingers;•the folds of the wrist,
•elbow or knee;
•the penis;
•the breast;•and/or the shoulder blades.
8/16/2019 12 - parasitic skin disease.pdf
16/29
Pediculosis
Causative agent:
- Pediculus humanus
- Phtirus pubis
8/16/2019 12 - parasitic skin disease.pdf
17/29
OrdoOrdo ANOPLURAANOPLURA
(Sucking lice)(Sucking lice)
OrdoOrdo ANOPLURAANOPLURA
(Sucking lice)(Sucking lice)
•• Wingless ,Wingless , dorsodorso--ventrally flattenedventrally flattened
•• The body is notThe body is not chitinizedchitinized..
•• Head is longer than it’s wideHead is longer than it’s wide•• well adapted to an existence on the body /bodywell adapted to an existence on the body /body--hairs.hairs.
•• Lice are host and site specific.Lice are host and site specific.
8/16/2019 12 - parasitic skin disease.pdf
18/29
Fam.Fam. PediculidaePediculidaeFam.Fam. PediculidaePediculidae
• Pediculus humanus var. capitis
• Pediculus humanus var. corporis
• Phthirus pubis
P. humanus var. capitis P. humanus var. corporis
8/16/2019 12 - parasitic skin disease.pdf
19/29
P. humanus var. corporis
P. humanus var. capitis
8/16/2019 12 - parasitic skin disease.pdf
20/29
8/16/2019 12 - parasitic skin disease.pdf
21/29
Pediculus humanus Pediculus humanus
The Morphology of Adult liceThe Morphology of Adult lice•• Female is bigger than maleFemale is bigger than male•• HaveHave greyishgreyish colour colour •• Head :Head :
-- rectangular rectangular--ovoidovoid from the dorsal aspectfrom the dorsal aspect
-- piercing and sucking proboscispiercing and sucking proboscis•• Thorax : 3 segmentsThorax : 3 segments externally indistinctexternally indistinct3 pairs legs, each ending in a claw3 pairs legs, each ending in a claw
•• Abdomen : 9 segments Abdomen : 9 segmentsthe terminal segments :the terminal segments :
femalefemale inverted Vinverted V-- shapedshaped
gonopodsgonopods in ventral sidein ventral sidemalemale roundedrounded
havehave aedeagusaedeagus
The Morphology of Adult liceThe Morphology of Adult lice•• Female is bigger than maleFemale is bigger than male•• HaveHave greyishgreyish colour colour •• Head :Head :
-- rectangular rectangular--ovoidovoid from the dorsal aspectfrom the dorsal aspect
-- piercing and sucking proboscispiercing and sucking proboscis•• Thorax : 3 segmentsThorax : 3 segments externally indistinctexternally indistinct3 pairs legs, each ending in a claw3 pairs legs, each ending in a claw
•• Abdomen : 9 segments Abdomen : 9 segmentsthe terminal segments :the terminal segments :
femalefemale inverted Vinverted V-- shapedshaped
gonopodsgonopods in ventral sidein ventral sidemalemale roundedrounded
havehave aedeagusaedeagus
8/16/2019 12 - parasitic skin disease.pdf
22/29
Lice eggHair Louse
8/16/2019 12 - parasitic skin disease.pdf
23/29
8/16/2019 12 - parasitic skin disease.pdf
24/29
Life CycleLife Cycle
• Incomplete metamorphose
• Eggs :
– Ovoid, operculated, white, cemented to the hair or
fiber• At body temperature they hatch in 4-14 days Nymph
Adult within 2 weeks
• The adult live about 30 days
8/16/2019 12 - parasitic skin disease.pdf
25/29
Medical ImportanceMedical Importance
8/16/2019 12 - parasitic skin disease.pdf
26/29
8/16/2019 12 - parasitic skin disease.pdf
27/29
8/16/2019 12 - parasitic skin disease.pdf
28/29
8/16/2019 12 - parasitic skin disease.pdf
29/29
• Habitat : – Pubic hair,
– Axillary, chest and body hair,
– Eyelashes and eyebrows
• Life cycle ~ Pediculus spp. (Phthirus: 15 d)
• symptomscaused by a bite, saliva
• Transmission: direct contact
• Tx ~ Pediculus spp.
Top Related