Laboratory and other diagnostic tests in dermatology Flashcards
What should lab tests be chosen based on?
Differentail diagnoses proposed
What do skin scrapings demonstrate?
Ectoparasites, dermatophytes and nematoes
Especially mites
What does the Wood’s Lamp test for?
Certain species of dermatophyte
What diseases can hair plucks demonstrate?
Ectoparasites, dermatophytes and hair structure
Especially demodex
What are coat brushings used to check?
Superficial ectoparasites
What diseases do tape strips test for?
Superficial ectoparasites or microbes
Especially yeasts
What do smears indicate?
Cytology of inflammatory cell type and microbes
What are cultures useful to show?
Bacterial or fungal organisms
What are biopsies used to diagnose?
Histopathological features or sample for culture
What can tests be used for other than diagnosis?
For monitoring treatment
What are intra-dermal skin tests used for?
Diagnosis of immediate hypersensitivity or atopic disease
What can be done if diagnostic tests don’t achieve a definitive diagnosis?
Treatment trial of most likely DDx
When is trail therapy not indicated?
If lengthy, expensive and potentially toxic treatment is required
How are skin scrapings performed?
On a well clipped area of hair using a No. 10 blade
