SA Lecture #9

What is a primary lesion?

lesions caused by a disease

What is a secondary lesion?

Lesion is a result of treatment or due to self-trauma

Macule

Primary - small, flat, well-circumscribed color change; freckle; <1 cm

Patch

Primary - flat, well-circumscribed area of color change; >1cm

Papule

Primary - small, solid, raised, round "bump" < 1 cm

Plaque

Primary - well-cirucumscribed, solid, elevated lesion > 1cm; may be a coalescing of papules

Wheal

Primary - rapidly appearing, raised area of skin; typically pruritic, typically allergic in nature; a.k.a; hive

Pustule

Primary - Raised, round nodule filled with pus; - a pus filled papule

Vesicle

Primary - small, raised, round nodule filled with clear fluid; <1cm; blister

Bulla

large besicle; >1cm

Nodule

Primary - General term for small collection of tissue distinctly palpable from surrounding tissues; can extend into deeper layers

Papilloma

Primary - wart

Tumor

Primary - a neoplastic (cancerous) mass

Epidermal collarette

Secondary - Roughly circular lesion remaining at the periphery of a ruptured pustule

Scale

Secondary - a clump or conglomeration of epithelial cells resembing a fish scale, dandrugg

Crust

Secondary - Dried exudate (sebum, pus, blood, etc)

Erosion

secondary - loss of some or all of the peidermis leaving a denuded surface

Ulcer

secondary - crater-like, open soe through the skin or mucous membranes

excoriation

Secondary - area of scratched-off skin, typically self-induced

Comedone

secondary - impacted hair follicle/pore containing plug of sebum and keratin debris; blackhead

Hyperkeratosis

Secondary - Hypertrophy of the stratum corneum; thickening of outer layer of skin. Excess keratin (ear)

Hyperpigmentation

Secondary - increased deposit of melanin within the skin (darkening of the skin)

Lichenification

Secondary - thickened, leathery skin; elephantine skin; resembling lichen

Erythema

Secondary - increased redness of the skin

Scar

Secondary - Fibrous tissue replacing normal skin after an injury; healing

Alopecia

secondary - hair loss

What are the two most common dermatophytes in small animals?

Microsporum canis and Trichophyton spp.

What must you allow a Woods Lamp to do before using it?

It must be allowed to warm up for 6-10 minutes before use

What causes false positives a lot when testing for dermatophytes?

Alternaria spp.

no more than ___ to ___ days between first appearance of colony and color change in DTM

3 to 5 days

DTM

Dermatophyte Test Media

Four ways to test for Dermatophytes

-Woods lamp

-Trichogram (hair suspended in mineral oil under scope)

-KOH digestion

-DTM