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100 terms

Dermatology - Skin Lesions

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What are initial eruptions that develop as a direct reflection of underlying disease?
primary lesions
What types of primary lesions exist (8)?
papule, pustule, vesicle, wheal, nodule, macule, tumor, cyst
Pink/red, raised, solid, circumscribed elevation (usu 1mm-few mm but up to 1cm)
papule
small, roundish, epidermal elevation that contains pus (like whitehead pimple)
pustule
small up to 1cm, epidermal elevation with clear fluid, like blister
vesicle
Raised, well-circumscribed, edematous lesion
wheal
hives = urticaria
well-circumscribed, solid lesion that usually occurs deep within the skin
nodule
circumscribed, flat, nonpalpable, small (up to 1cm) spot of skin color change
macule
mass involving the skin or subcutaneous tissue
tumor
epithelium-lined cavity that is filled with solid or fluid material
cyst
What type of lesion may occur due to chewing, scratching, trauma etc, the result of infection or evolve from a ___ lesion?
secondary
may evolve from primary
What types of secondary lesions are there (7)
epidermal collarette, lichenification, callus, fissure, erosion or ulcer, scar, excoriation
What does a papule indicate?
cellular infiltrate - usu represents inflammatory lesion
Does a papule involve hair follicles?
may or may not
What are common causes of papules in dogs & cats?
dogs - bact skin dz (incl pyoderma) & ectoparasites
cats - less common but hypersensitivity/allergic dermatitis, infected feline acne
less common both dogs & cats: pemphigus & contact reactions
What cells do pustules usu contain, and what is less common?
more common NP
less common eos
T/F Pustules always indicate bacterial infection.
False. Can be sterile with pemphigus foliaceus - but less common.
Are pustules sturdy?
no, fragile, rupture easily - may just see ulcer after.
Are vesicles seen commonly?
no, occur infrequently and rupture easily
What are common causes of vesicles?
autoimmune skin diseases, irritant reactions, burns
What is a vesicular lesion >1cm in diameter?
bulla
Describe the skin around a wheal
Usually normal
How long do wheals last?
minutes to hours - short lived
Are wheals a frequent finding?
no - uncommon in dogs, rare in cats
What causes wheals?
insect bites, or non-insect related allergic reactions
What are causes of nodules?
Inflammatory or neoplastic cellular infiltration in the dermis or subcutis
What is a neoplastic nodule called?
tumor
A macule larger than 1cm diameter is a ?
patch
T/F: all macules are hyperpigmented, and erythematous
F - can be hyper or hypo, erythematous or hemorrhagic
Are macules commonly seen?
Yes, in dogs as a postinflammatory, hyperpigmented change
Are tumors neoplastic?
yes
Describe the texture of cysts?
soft/floculant or firm. Follicular are often firm
A circular ring of scale/peeling keratin
epidermal collarette
Thickening of the skin, characterized by an exaggeration of the normal skin surface markings
Lichenification
A thickened, rough, alopecic, hyperkeratotic plaque like lesion
callus
A linear cleavage into or through the epidermis - crack in skin
fissure
epidermal defect that does not penetrate the BMZ and heals without scaring
erosion
epidermal defect that is deeper than an erosion, exposes dermis and often heals with scarring
ulcer
fibrous tissue replacement of normal epidermis, dermis or subcutis
scar
Erosions or ulcers resulting from self-trauma (excessive scratching, biting, rubbing)
excoriation
What is often a remnant of a papule or pustule?
epidermal collarette
What results from friction and is often indicative of chronicity?
lichenification
What is commonly seen over bony areas and is caused by pressure and friction?
callus
Where are fissures found and are they found frequently?
footpads, ear margins, nasal, oral or anal mucocutaneous junctions
Uncommon but with various disease etiologies, including trauma.
Self-trauma, and conditions affecting the epidermis may lead to a ?
erosion
infection, neoplasia, vasculitis, certain autoimmune skin diseases and burns may lead to ?
ulcers
Burns or deep infections may cause
scars
Often created in response to pruritis, less commoly pain
excoriation
Lesions that can be either primary or secondary (7)
alopecia, scale, crust, follicular cast, comedo, pigmentary abnormalities, erythema
Abnormal hair loss =
alopecia
partial abnormal hair loss
hypotrichosis or partial alopecia
Accumulation of loose, cornified skin cells (flaky skin, dandruff)
scale
dried exudate, serum, cells, blood, scales (a scab)
crust
a cylindrical accumulation of keratin that is adhered to (surrounds) a hair shaft
follicular cast
a plugged follicle that contains keratin (and may contain sebum and cornified skin cells)
comedo
Describe the different pigmentary abnormalities (5)
hyper, hypo pigmentation, malanotrichia (excess hair pigment), leukotrichia (lack of hair pigment) leukoderma (nonpigmented skin)
excessive hair pigment =
melanotrichia
lack of hair pigment vs nonpigmented skin
leukotrichia vs leukoderma
redness of the skin often due to congestion of skin capillaries
erythema
Endocrine diseases and follicular dysplasias may cause ___ alopecia.
primary
Skin infections, inflammation of the skin and self-induced trauma may cause ___ alopecia.
secondary
Primary seborrhea, ichthyosis, follicular dysplasia and sebaceous adenitis may cause ____ scale.
primary
Common and non-specific, occurs with many infections and inflammatory conditions ____ scale.
secondary
Zinc-responsive dermatosis and in some cases primary seborrhea occur with ___ crusting.
Primary
Pyoderma and pruritic dermatoses and many dermatoses occur with ___ crusting.
secondary
Sebaceous adenitis and primary seborrhea associate with ___ follicular casts.
primary
Dermatophytosis and demodicosis are associated with ___ follicular casts.
secondary
Hypopgimentation from vitilago is an example of ___ pigment abnormality.
primary
A common postinflammatory change in dogs is ____ hyperpigmentation.
secondary
A common result from a variety of different dermatologic conditions.
erythema
Configuration of skin lesions
Number
single or multiple
Config of skin lesions: shape
annular (ring), linear or serpiginous or other
Shape seen with bacterial folliculitis, dermatophytosis, demodicosis
annular pattern
Shape seen with excoriations, external forces, lesions with vessel involvement, some congenital conditions
Linear
Having wavy, indented or undulating margins =
serpiginous
Which diseases have diffuse distributions?
some endocrine, allergic and keratinization defects
T/F we often see the original lesion
False - lesions change as they progress - often see footprints of the lesion
What are the 10 parts of history to dx?
Signalment
Chief complaint
Onset of derm prob
Disease progression
Past response to tx
seasonality
pruritic?
enviornmental & dietary history
other animals/people with problem
any non-derm dz present?
What part of signalment can be important for some dermatoses?
coat color
Physical exam - 6 components?
1) good overall PE
2) skin - what lesions present
3) configuration of lesions
4) distribution of lesions
5) pruritic?
6) painful? - rare
T/F painful skin conditions are common
False - rare
Lab procedure good for detecting ectoparasites such as mites?
skin scrapings
Lab procedure good for finding ectoparasites including Cheyletiella and fleas
flea combing
Lab proceedure to find ectoparaisites, esp cheyletiella
acetate tape impressions
What can be used to assess self-induced alopecia, dermatophytes, ectoparasites, color distribution alopecia, hair dysplasias, hair shaft abnormalities, hair growth stage (anagen vs telogen)?
hair examination (trichography)
What is used to look at cell types as indicators of infection, autoimmune dz, neoplasia, allergy, ectoparasite etc - and sometimes see infectious organisms?
cytology
What is the most reliable way to detect dermatophytes?
culture
What is useful for deeper fungal infections and some, esp deep bacterial skin infections?
culture
What is used to assess dermatophytosis but not great?
Wood's lamp - only 50% flouresce
What is necessary to definitively diagnose certain derm conditions?
Biopsy and dermatohistopathology
When a condition does respond to appropriate therapy what do you do?
biopsy & dermatohistopathology
For unusual or serious dermatoses or suspected autoimmune conditions - test?
biopsy & dermatohistopathology
For conditions that aren't easily diagnosed w/o biopsy - test?
biopsy & dermatohistopathology
For persistent ulcerated dermatoses - test?
biopsy & dermatohistopathology
For vesicular conditions - test?
biopsy & dermatohistopathology - rare
For suspected dermatoses for which treatment may be dangerous - test?
biopsy & dermatohistopathology
For possible neoplastic lesions - test?
biopsy & dermatohistopathology
What types of allergy testing are available?
intradermal or skin
in vitro testing - serologic
diet trial for food allergy
patch testing - rare
When are bloodwork and urinalysis helpful?
Cases of endocrinopathy and certain autoimmune conditions. For most derm cases - little diagnostic value
What other tests might be used?
Antinuclear antibody (ANA) to evaluate thyroid hormone, screening and differentiating tests for hyperadrenocorticism