dermatology

1. Parasites
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2. •Parasite - organism that depends
on a living host for one or more
of its metabolic requirements.
•Ectoparasite
•Endoparasite
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3. 3
ECTOPARASITES
SCABIES
PEDICULOSIS
ENDOPARASITES
PROTOZOA-
LEISHMANIA
HELMINTHES-
ONCOCERCIASIS
FILARIAISS

4. Ectoparasites
Scabies
pediculosis
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5. SCABIES
• mite Sarcoptes scabiei,
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6. • Adult male + adult female ( 4 pairs of legs)
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copulation
Female starts making burrows in
stratum corneum and lays eggs

7. • eggs
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Larvae ( three pair of legs)
3-4 days
Protonymph
tritonymph
3-4 days
2-3days
2-3days
Adult

8. Direct Transmission
• direct skin contact between two
individuals.
• About 15-20 mins of close
contact is adequate for
transmitting the disease.
• Family overcrowding.
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9. PATHOGENESIS
•Allergic sensitivity to the mite or
its products
•both immediate and delayed type
hypersensitivity are involved.
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10. •In primary infestation, the
symptoms appear slowly after a
lapse of about 4-6 weeks.
•Reinfection- 24-48 hrs
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11. CLINICAL FEATURES
1. Pruritis
• intensifies at night.
• result of a systemic allergic
reaction to the mite, its eggs, and
excreta (fecal pellets/ scybala),
mite proteins.
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12. 2.Burrows
• pathognomonic
• threadlike, grayish
3.Excoriated papules
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13. Sites of
predilection
circle of
hebra
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14. • Interdigital folds
• Flexor aspects of the wrists
• Elbow, axillae
• Nipple & areolae(in females),
• Periumbilical skin, lower abdomen(waistline),
• Scrotum & penis (males)
• Intergluteal cleft, buttocks
• Feet ,ankle
• An imaginary circle intersecting the main sites of
involvement—axillae, elbow flexures, wrists and
hands, and genitalia—has long been called the
circle of Hebra.
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15. VARIANTS
Nodular scabies
• firm, reddish brown, extremely
pruritic, excoriated nodules,
• Male genitalia, groins
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16. Scabies in infants and young children
• frequent involvement of the scalp, face
palms, and soles.
• vesicles
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17. Bullous scabies
• mimic bullous pemphigoid
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18. Crusted scabies
• hyperkeratotic crusted lesions
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19. INVESTIGATIONS
• Microscopy- demmonstration ofmite
• Histopathology
• Dermoscopy-jet and contrail appearance
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20. Treatment
TOPICAL
• Precipitated sulphur
• Benzyl benzoate
• 1% lindane (BHC)
• Crotamiton 10%
• 5% permethrin
• Others
ORAL
• Ivermectin
200microgram/kg
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21. • Permethrin acts on the nerve cell
membrane of the arthropod by
disrupting the sodium channel
current
Used as 5% Cream, rinsed off after
8–14 hr .repeated after 7 days
•Pregnancy
–Pregnancy Category B
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22. ivermectin
• 200 mcg/kg orally.
• Often repeated in 7-14 days
• Lack of ovicidal activity.
• glutamate-gated chloride ion channels. leads
to hyperpolarization of the nerve or muscle
cell and death.
• Pregnancy
– Pregnancy Category C
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23. Pediculosis
Pediculus capitis-head louse
Pediculus humanus- body louse
Pthirus pubis- pubic louse
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24. • treatment
• 1% permethrin applied for 8-10 mins.
• Treatment repeated in 7-10 days.
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25. Endoparasites
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26. PROTOZOA
LEISHMANIA
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27. • Leishmaniasis
• It is a flagellate protozoan
• sand fly or in culture---promastigote
form
• the cells of the host reticuloendothelial
system--------- amastigote
.
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28. . The insect vector of Ieishmaniasis is
the female sand fly.
Old world-----------------------Phlebotomus
genera.
New world----------------------Lutzomyia
genera.
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29. Cutaneous leishmaniasis
1) Old World Cutaneous Leishmaniasis.
OW-CL (, Baghdad boil, Oriental sore,, Delhi
boil etc).
• Two major types are identified
• MOIST OR RURAL TYPE
• DRY OR URBAN TYPE
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30. • MOIST OR RURAL TYPE.
• L. Major
• multiple lesions,
• short incubation period (1 week to 3
months),
• rapid and mild course, and
• good response to therapy.
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31. • DRY OR URBAN TYPE.
• L. tropica
• longer incubation period and
course (twice as long as in the
moist type)
• worse response to therapy.
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32. • erythematous papules
• nodules/plaques
• The "volcanic" nodulo-ulcerative
morphology is characteristic
• Regional lymphadenopathy,.
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33. 2)Diffuse cutaneous leishmaniasis
• L.aethiopica
• Diffuse involvement
• Nodules ----never ulcerate
• +++++++parasites
• Internal organs not involved
.
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34. 3) New World Cutaneous
Leishmaniasis.
• also known as valley sickness, , white
leprosy,
• caused by L. mexicana -chiclero ulcer,
a chronic mutilating infection of the
pinna of the ear of forest workers in
Mexico and Central America.
• L. braziliensis complex.- Destructive
mucosal lesions are seen k/s Epsundia.
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35. 4) PKDL
• the most common skin manifestation of
leishmaniasis.
• It develops after the visceral disease has
healed spontaneously or following treatment
• .In india it presents as hypopigmented
macules which later develop nodular lesions
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36. • Diagnosis
• Demonstration of amastigotes from bone marrow,
spleen and LN for VL and from ulcers (CL), mucosal
lesions(ML) is required for diagnosis.
• Monoclonal Antibodies.
• Culture. Novy-MacNeal-Nicolle
• Serology
• Leishmanin skin test
• DNA- PCR
• Napiers aldehyde test
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37. treatment
• Ampho b
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38. Helminths
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Onchocerciasis
Lymphatic filariasis

39. •ONCHOCERCIASIS
•river blindnes.
•Vector –black fly of the family
simuliidae.
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40. • Clinical features.
• Six different patterns of skin changes have
been described:
• acute papular onchodermatitis,
• chronic papular onchodermatitis,
• Lichenified onchodermatitis,
• atrophy,
• depigmentation
• palpable onchocercal nodules
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41. • Laboratory tests:
• Peripheral eosinophilia and elevated IgE
levels
• Special Tests.
• identification of microfilariae in a skin snip
or of an adult worm in an excised nodule.
• Microfilariae may be clearly visible in the
anterior chamber of the eye on slit-lamp
examination.
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42. • Treatment
• Drug of choice is Ivermectin given in a
single dose of 100-200 ug/kg.
• Repeated every 6 monthly
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43. • Lymphatic filariasis
• W. bancrofti -transmitted by Culex
quinquefasciatus,
• B. malayi -Mansonia
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44. • Clinical features
• M/c presentation is asymptomatic
microfilaremia.
• Microscopic heamaturia/proteinuria
• Lymphangitis and lymphadenitis
• Elephantiasis
• varicocele
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45. • Diagnosis
• Made by demonstrating Mf in peripheral blood,
hydrocele fluid.
W.Bancrofti has no nuclei at the tip of tail
B.Malayi has 2 prominent nuclei.
• immunochromatographic card test
• DNA PCR
• Doppler USG can detect live worms which have a
particular pattern of movement in lymphatics k/s the
filaria dance sign.
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46. • Treatment
• DEC is the drug of choice.- 6mg/kg for 12 days.
Others
• Albendazole.
• Ivermectin(400ucg/kg)
• doxicycline
• Lymphedema management
• Limb elevation
• Compression stockings
• Surgical treatment.
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