Skin scraping test

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 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 Bachrach H. L (1968): Foot-and-mouth Disease. Ann. Rev. Microbiol . 22, 201-244 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 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 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