Dermatology - Diagnostic Approach and Procedures Flashcards
What are the top three dermatology-related problems?
otitis externa, allergies, and pyoderma
What are the key diagnostic tools that should be used to facilitate management of skin problems?
skin scrapings, impression smears of yeast, trichogram, and cytology of appropriate lesions
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 _____).
multifaceted; underlying; infection
What is the ‘key’ to diagnosing and treating all dermatological issues?
First, identifying all factors involved and then controlling all secondary issues
After secondary infections are controlled, what is a necessary next step?
a recheck examination
What are the steps to a dermatology case workup?
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
What information is important to get during the initial visit of a patient with dermatological issues? (Non-specific)
signalment, history, and physical examination
True or False: Data base tests are only performed when there is evidence of damage to the epidermis.
False - they should be performed in every case at every visit
What should happen during a dermatology recheck examination?
- Evaluation of your previous therapy for perpetuating factors revealed at first visit
- Re-visitation of the dermatologic history
- Repeat the data base - because things change!
When taking a history for a dermatology case, what information should you make sure to get?
The past medical history, the environmental history, the dietary history, and the history of the present problem
With what type of dermatologic disease should skin scraping techniques be used on?
all types - it should be done on all animals with dermatologic disease
What materials are needed for a skin scrape?
10 scalpel blade (dull is better), mineral oil, glass slides, clippers, and a microscope
How do you perform a skin scrape?
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.
Which mites are easily recovered in skin scraping?
Demodex canis
Which mites are difficult to find in skin scrapings?
Sarcoptes, D. gatoi, and D. injai
When are smears for Malassezia performed?
Whenever yeast are suspected as a primary or secondary cause of pruritis, scaling, erythema, or seborrhea
What materials are needed for an impression smear?
glass sides, scotch tape, clippers, cotton swab, microscope slide, microscope, and appropriate stains
True or False: There should no hair in the area that an impression smear is going to take place.
TRUE
True or False: You should always heat fix an impression smear in order to get a diagnosis.
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.
When doing impression smears, where are cotton-tipped applicator swabs useful?
In hard to reach places such as skin fold areas and the ear canal
How do you transfer a cotton-tipped applicator sample to a slide?
roll pressing firmly - do not rub
How can you use regular glass microscope slides to take an impression smear?
press it directly and firmly against the skin several times - make sure to wear gloves
What is the best objective to view Malassezia on?
40x - then the oil objective if needed
What is a trichogram used for?
to evaluate the integrity of hair shafts and also serves as a test for demodicosis and dermatophytosis
What materials are needed for trichograms?
forceps, mineral oil, glass slides, cover slips, and a microscope
How are trichograms performed?
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
What are hair follicles in trichograms examined for?
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
Where should hair samples for trichograms be collected from?
all over the body
When should fungal cultures be done?
In all dermatology cases
What materials are needed for fungal cultures?
forceps, culture media, glass slides, stains, cover slips, and a microscope
What materials can be cultured for fungal cultures?
hair samples, crusts from lesions, or nails - hair is preferred
What is the culturing process for fungal cultures?
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
Why should cultures be examined daily if a Dermatophyte Test Medium is used?
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
Should cytology be done in all dermatological cases?
Yes, because it is required for proper diagnosis of a problem and especially for proper quality control
