Dermatology - Diagnostic Approach and Procedures

Question 1

What are the top three dermatology-related problems?

Answer 1

otitis externa, allergies, and pyoderma

Question 2

What are the key diagnostic tools that should be used to facilitate management of skin problems?

Answer 2

skin scrapings, impression smears of yeast, trichogram, and cytology of appropriate lesions

Question 3

Dermatology problems are frequently __________. That is, there is often an _______ problem (such as an allergy) that is compounded by secondary problems or factors (such as _____).

Answer 3

multifaceted; underlying; infection

Question 4

What is the ‘key’ to diagnosing and treating all dermatological issues?

Answer 4

First, identifying all factors involved and then controlling all secondary issues

Question 5

After secondary infections are controlled, what is a necessary next step?

Answer 5

a recheck examination

Question 6

What are the steps to a dermatology case workup?

Answer 6

Step 1: The Initial Visit
Step 2: The Dermatology Data Base
Step 3: Manage Perpetuating Factors
Step 4: The Recheck Examination
Step 5: Identify the Primary Factors

Question 7

What information is important to get during the initial visit of a patient with dermatological issues? (Non-specific)

Answer 7

signalment, history, and physical examination

Question 8

True or False: Data base tests are only performed when there is evidence of damage to the epidermis.

Answer 8

False - they should be performed in every case at every visit

Question 9

What should happen during a dermatology recheck examination?

Answer 9

1. Evaluation of your previous therapy for perpetuating factors revealed at first visit
2. Re-visitation of the dermatologic history
3. Repeat the data base - because things change!

Question 10

When taking a history for a dermatology case, what information should you make sure to get?

Answer 10

The past medical history, the environmental history, the dietary history, and the history of the present problem

Question 11

With what type of dermatologic disease should skin scraping techniques be used on?

Answer 11

all types - it should be done on all animals with dermatologic disease

Question 12

What materials are needed for a skin scrape?

Answer 12

10 scalpel blade (dull is better), mineral oil, glass slides, clippers, and a microscope

Question 13

How do you perform a skin scrape?

Answer 13

First, clear the area from hair. Then, squeeze the area gently and release. Place mineral oil on the glass slide. Wipe the blade in oil, scrape the surface of the skin, and hold the plade perpendicular to the skin surface. The area should be 1.5x1.5 cm. Finally transfer to a slide and examine under 10x.

Question 14

Which mites are easily recovered in skin scraping?

Answer 14

Demodex canis

Question 15

Which mites are difficult to find in skin scrapings?

Answer 15

Sarcoptes, D. gatoi, and D. injai

Question 16

When are smears for Malassezia performed?

Answer 16

Whenever yeast are suspected as a primary or secondary cause of pruritis, scaling, erythema, or seborrhea

Question 17

What materials are needed for an impression smear?

Answer 17

glass sides, scotch tape, clippers, cotton swab, microscope slide, microscope, and appropriate stains

Question 18

True or False: There should no hair in the area that an impression smear is going to take place.

Answer 18

TRUE

Question 19

True or False: You should always heat fix an impression smear in order to get a diagnosis.

Answer 19

False - you do not always need to heat fix it. It is possible to get a diagnosis without heat fixing it, there are just less organisms. You can also ‘cook’ your cells by overheating and ruin your sample. If you use a hairdryer to dry, make sure to use cool air to avoid overheating.

Question 20

When doing impression smears, where are cotton-tipped applicator swabs useful?

Answer 20

In hard to reach places such as skin fold areas and the ear canal

Question 21

How do you transfer a cotton-tipped applicator sample to a slide?

Answer 21

roll pressing firmly - do not rub

Question 22

How can you use regular glass microscope slides to take an impression smear?

Answer 22

press it directly and firmly against the skin several times - make sure to wear gloves

Question 23

What is the best objective to view Malassezia on?

Answer 23

40x - then the oil objective if needed

Question 24

What is a trichogram used for?

Answer 24

to evaluate the integrity of hair shafts and also serves as a test for demodicosis and dermatophytosis

Question 25

What materials are needed for trichograms?

Answer 25

forceps, mineral oil, glass slides, cover slips, and a microscope

Question 26

How are trichograms performed?

Answer 26

Mosquito forceps are used to firmly grasp several hairs and then pull them from the follicle. The hair samples should be placed in a drop of mineral oil, all in the same direction, on a microscope slide and then covered with a cover slip. They are to be examined immediately

Question 27

What are hair follicles in trichograms examined for?

Answer 27

Type of hair, structural damage to hairs supporting the presence of pruritus or other abnormalities, evidence of dermatophytosis, ectoparasites, the stage of hair growth, and pigmentary abnormalities

Question 28

Where should hair samples for trichograms be collected from?

Answer 28

all over the body

Question 29

When should fungal cultures be done?

Answer 29

In all dermatology cases

Question 30

What materials are needed for fungal cultures?

Answer 30

forceps, culture media, glass slides, stains, cover slips, and a microscope

Question 31

What materials can be cultured for fungal cultures?

Answer 31

hair samples, crusts from lesions, or nails - hair is preferred

Question 32

What is the culturing process for fungal cultures?

Answer 32

The sample should be placed on a culture, incubated at 30 degrees Celcius and 30 percent humidity. They should be observed daily for growth for at least 10 days and then perioddically for a total of four weeks. After a colony gorws, hyphae should be teased apart, put on a slide, stained, a cover slip placed on top, and examined microscopically

Question 33

Why should cultures be examined daily if a Dermatophyte Test Medium is used?

Answer 33

It contains a color indicator that usually turns red if the fungi creates alkaline metabolites. However, saprophytic fungi use the carbohydrate in the medium, producing acid metabolites, and no color change. However, after the carb is exhausted the saprophyte will utilize the protein and the color will change red

Question 34

Should cytology be done in all dermatological cases?

Answer 34

Yes, because it is required for proper diagnosis of a problem and especially for proper quality control