Procedure total

1. Skin Scraping Test
Submitted By
ID No.: 18 VMED- JJ 10M
18 VMED- JJ 12M
18 VMED- JJ 13M
Course No.: VM 604
Course Title: Veterinary Diagnostic Medicine
Submitted To
Dr. Md. Amimul Ehsan
Professor
Dept. of Medicine

2. Outline
 Introduction
 Objectives
 Advantages
 Instruments and appliances
 Principles of collection and examination
 Deep skin scrapings
 Superficial skin scrapings
 Skin scraping for KOH examination
 Scraping for scabies

3. Introduction
 A skin scraping is a collected sample of skin cells
that are evaluated under a microscope
 This tests are performed to aid in diagnosing
 Skin inflammations
 Fungal infections
Many types of parasitic skin infestations
Skin cancer
The presence of mites

4. Objectives
 To examine parasitic infections such as
Stephanofilariasis, mange, mite etc
 To diagnose skin disease
 To identify the causal agent
 To know the morphology of adult parasite,
microfilaria, eggs and larvae
 To treat animals properly

5. Advantages
 One of the most common dermatologic
diagnostic tests
 Relatively simple and quick test
 The relative ease and low cost makes it an
essential test in a dermatological minimum data
base
Alexandersen S et al., 2003

6. Instruments and appliances
 Scalpel
 Scissors
 Microscope

7. Contd..
 Glass slide
 Cover slip
 Mineral oil

8. Contd..
 Antiseptics solution
 10% KOH solution

9. Principles of collection and
examination
A scalpel blade is used to collect the material from the
skin surface
If these are to be reused, they need to be washed and
disinfected
If the scraped area is covered with hair then clipping
is better to access the skin surface
Put some mineral oil on the skin surface to facilitate
collection of the scraped sample

10. Contd…
Hold the spatula perpendicular to the skin surface
Scrape in the direction of the hair
Pick up the entire scraped sample on the edge of the
spatula
Transfer the sample to a drop or more of mineral oil
on a glass slide

11. Contd…
Spread the material around in the mineral oil to get an
evenly distributed sample
Potassium hydroxide 10% is added to the collected
material to digest unwanted tissue
Apply a cover slip
Examine with the 10x microscope objective
Bachrach H. L., 1968

12. Contd…
 When examining a skin scraping versus a cytology
slide, keep the sub- stage condenser down
 To maximize contrast for better visualization of
parasites
 This is especially important for small life stages such
as Demodex eggs
 Occasionally, higher magnification may be needed
 But 10x is adequate for most of the common skin
parasites

13. Contd…
Fig: Sample collection for skin scraping test

14. Deep skin scrapings
 Used to examine for parasites that reside in the hair
follicles, especially Stephnofilaria assamensis,
Demodex canis and Demodex cati
Fig: Deep Skin Scraping

15. Contd…
Procedure:
 Again, all of the general principles apply
 Since these mites are usually easier to find, smaller
areas can be examined
 However, multiple areas on the body may still need
to be examined such as
 the face, head, feet and other lesional areas for
Demodex

16. Contd…
The two most important additional steps are
 squeeze the area to be scraped to help extrude
the mites from the follicles to the surface and
 Scrape with moderate pressure until blood oozes
from the superficial capillaries
Gunes V. H., 2005

17. Contd…
 In hard to scrape areas such as
 Around the eyes, gently plucking hairs and examining
the shafts in mineral oil may help visualize mites
 In scarred and edematous areas such as
 The feet and in certain breeds such as Shar peis and
Shih Tzu’s
 It may be impossible to find follicular mites without a skin
biopsy

18. Superficial Skin Scrapings
 Used to examine for parasites that reside on or near
the skin surface such as Sarcoptes, Notoedres,
Cheyletiella, Otodectes and chiggers
Fig: Superficial Skin Scraping

19. Contd…
Procedure:
 All of the general principles apply
 Some of the superficial mites are in small numbers
and may be hard to find
 Larger area of skin using several strokes with mild
to moderate pressure without the need for surface
capillary bleeding
Donaldson A. I., 2007

20. Contd…
More than one slide for the hard to find parasites
Put some mineral oil directly on the skin surface
Since dry debris is hard to pick up and transfer to the
microscope slide
Fig: Administration of mineral oil

21. Skin scraping for KOH
examination
 Involves microscopic examination of stratum
corneum to visualize fungal elements
 KOH solution causes separation and destruction
of the stratum corneum cells
 This allows easy identification of exogenous
materials such as
 Hyphae and spores which are unaffected by the
KOH solution
Gulbahar M. Y et al., 2007

22. Contd…
Indications –
 Dermatophytosis of the skin, hair and nails
 Candidiasis
 Tinea versicolor

23. Contd…
Procedure-
Swab the site with spirit
Scrap the lesion at active border with
a 15 no. blade
Add 1-2 drops of KOH and put cover
slip
Wait for 15-20 min. for the keratin to
digest
Donaldson A. I., 2007

24. Contd…
Fig. Dermatophytes- multiple, refractile,
branched, septate hyphae

25. Contd…
Fig. Candidiasis- budding ovoid yeast
cells and pseudohyphae

26. Contd…
Fig. Tinea versicolor- hyphae with clusters of
spores , often called “spaghetti and meatballs”

27. Scraping for scabies
 After applying a drop of mineral oil, the burrow is
scraped with a 15 no. scalpel blade
 Scraping transferred to glass slide and seen
under microscope
 Reveals mite, eggs or fecal pellets
Alexandersen S et al., 2003

28. Contd…
Fig. Scabies Under Microscope

29. References
1. Alexandersen S., Z. Zhang, A. I. Donaldson, A. J. M.
Garland (2003): The Pathogenesis And Diagnosis Of Foot-
and-mouth Disease. J. Comp. Pathol. 129, 1-36
2. Bachrach H. L (1968): Foot-and-mouth Disease. Ann. Rev.
Microbiol. 22, 201-244
3. Donaldson A. I., R. F. Sellers (2000): Foot-and-mouth
Disease. In: Diseases Of Sheep. (Martin, W. N., I. D. Aitken,
Eds). Blackwell Science, Oxford, United Kingdom. Pp. 254-
258
4. Gulbahar M. Y., W. C. Davis, T. Guvenc, M. Yarim, U. Parlak,
Y. B. Kabak (2007): Myocarditis Associated With Foot-and-
mouth Disease Virus Type O In Lambs. Vet. Pathol. 44, 589-
599
5. Gunes V., H. M. Erdogan, M. Citil, K. OZCAN (2005): Assay
Of Cardiac Troponins In The Diagnosis Of Myocardial
Degeneration Due To Foot-and-mouth Disease In A Calf.
Vet. Rec. 156, 714-715