Skin and Hair Sampling

Question 1

What equipment would you need to set up for all skin and hair sampling?

Answer 1

PPE - gloves, mask, gown
Brush, comb, toothbrush
Tape
Forceps
Paper
Biopsy punches - clippers, scrub, stitch up kit
Liquid paraffin
Microscope slides
Surgical blade
Swabs

Question 2

What are coat brushing samples good for?

Answer 2

Useful in diagnosing ectoparasites and their eggs (especially Cheyletiella)

Question 3

Describe the technique for a coat brushing sample

Answer 3

Part hair
Brush small areas, one at a time, in one direction
Tap the brush onto the petri dish, or onto a microscope slide with liquid paraffin and a cover slip

Question 4

What can be done to test for fleas?

Answer 4

Put flea dirt onto white paper and dampen - will look like blood

Question 5

What are the advantages of coat brushing samples?

Answer 5

Easy to perform, can be done in front of owner
Non-invasive
Not stressful or painful for patient
Cheap
Quick

Question 6

What can tape testing techniques used for?

Answer 6

Ectoparasites and some yeasts (if stain the tape)

Question 7

Describe the technique for a tape test

Answer 7

Part the hair or lightly clip
Gently press the tape on the hair and skin
Stick the tape directly onto a microscope slide if looking for ectoparasites and examine
For yeast, use scotch tape and use a diff-quick method.

Question 8

What are the advantages of the tape technique?

Answer 8

Cheap
Easy technique
Quick results
Can be used to reach hard to access areas e.g. in between the paw pads

Question 9

What are the disadvantages of the tape technique?

Answer 9

Can only be used in dry areas

E.g. if there is a ‘raw’ area where secondary infection is present then it wouldn’t be appropriate.

Question 10

Describe how to perform a hair pluck

Answer 10

Using tweezers or forceps, pluck a clump of hair (and roots!) out and examine. If there are lesions present, take hair from the edge of the lesion.

Question 11

What is a hair pluck generally used for?

Answer 11

To look for fungal infection or mites that live deep in the hair follicles

Question 12

What are the 3 ways in which hair plucks can be examined?

Answer 12

1. Microscope
2. UV light
3. Culture

Question 13

How can hair pluck samples be examined under the microscope?

Answer 13

Grossly to diagnose mites

To look for fungal infections, should be stained with lactophenol cotton blue.

Question 14

How is UV light used to check hair samples?

Answer 14

Using a Wood’s lamp in a dark room.
Hair may fluoresce a bright apple green if ringworm is present.
50% of Microsporum canis isolates will fluoresce the green colour.
Other things can fluoresce e.g. talc

Question 15

How would you culture a plucked hair sample?

Answer 15

The suspected hair sample is placed onto a culture plate containing Sabourards agar or Dermatophyte test medium (DTM).
DTM contains an indicator that changes colour from yellow to red in the presence of dermatophytes.
The plate should be incubated at room temperature and be checked on days 7,10 and 14

Question 16

What are the advantages of a plucked hair sample?

Answer 16

Quick and simple to obtain the sample from the patient

Question 17

What are the disadvantages of a hair pluck?

Answer 17

Can be painful
Only 50% of cases fluoresce under UV
May get a false positive under UV

Question 18

Describe the technique of a skin scrape

Answer 18

Scalpel blade is used to scrape the skin surface (deep enough to cause petechial bleeding).
Scraping should be placed onto liquid paraffin
The scraping can be put on a microscope slide for examination under the microscope. View immediately
Scraping should be taken from multiple areas on the body.

Question 19

What can be diagnosed by skin scraping

Answer 19

Mange mites usually

Question 20

What are the advantages of skin scraping?

Answer 20

Can diagnose deeper dwelling parasites
Quick results
Done ‘in-house’

Question 21

What are the disadvantages of skin scraping?

Answer 21

Can be painful/stressful
Need to the correct technique
Need to sample multiple sites

Question 22

What can you do to prevent dessication of a skin scrape sample if it cant be viewed straight away?

Answer 22

Suspend the sample over a petri dish containing blotting paper soaked with distilled water. Cover with a lid, seal and store in a cool dark place

Question 23

What is a pustule?

Answer 23

A bulging patch of skin that’s full of pus

Question 24

Describe how a pustule is sampled?

Answer 24

The contents extracted using a sterile needle and a 1-2ml syringe. It should then be expressed directly onto the microscope slide. It should then be squashed using another slide at a 45 degree angle. Samples can then be viewed at low power or stained and examined under high power.

Question 25

When are swabs used for sampling?

Answer 25

Generally in hard to reach places like ear canals

Question 26

How can a swab be tested?

Answer 26

By directly smearing onto a slide and viewing
Or collect and seal sterilely and send away
(if sending for a culture and sensitivity, a charcoal swab should be used)

Question 27

When is a biopsy punch used?

Answer 27

To take a sample of diseased skin when the skin problems are deeper than the epidermal layer.

Question 28

Is the patient conscious during a skin biopsy?

Answer 28

It can be done under light sedation and the patient is given a small stitch.
If its in a very sensitive area, it should be performed under GA

Question 29

What should you remember to do when admitting a patient for biopsies?

Answer 29

Warn the owner that it will look worse before it looks better!