Dermatology 2

Question 1

localized vs generalized skin conditions - what conditions generally fit these criteria?

Answer 1

o Localized may be more consistent with infections, most neoplasia (in the initial stages)
o “Inside out diseases” such as endocrine diseases, metabolic diseases and nutritional diseases may
be more generalized.
o Immune diseases can be either (e.g. discoid lupus can be localized to the nose)

Question 2

pinal-pedal reflex > correlated with what conditions?

Answer 2

• 82% of patients with scabies have a positive pinnal pedal reflex (90% if there is a pinnal dermatitis)
• but 6.2% of pruritic patients without scabies will also have a positive pinnal pedal reflex.

Question 3

loss of guard hairs may present how?

Answer 3

as a colour change

Question 4

retention of puppy coat suspicious of:

Answer 4

Alopecia-X

Question 5

Macule - what is it? what are different types and how can we tell them apart?

Answer 5

A well circumscribed non-palpable area of colour change less than 1 cm diameter (a “spot”).
 Pigment change can be due:
* to an increase or decrease in melanin (e.g., depigmenting diseases such as vitiligo, discoid lupus, uveodermatologic syndrome and inflammatory diseases (e.g. mucocutaneous pyoderma),
* hemorrhage (vasculitis). Wont blanche on diascopy
> Diascopy – press a clear slide against an erythematous area of the skin to see if it blanches with pressure
* vascular engorgement (erythema). Will blanche on diascopy

Question 6

Patch

Answer 6

A well circumscribed non-palpable area of colour change more than 1 cm diameter

Question 7

Plaque

Answer 7

A solid elevation more than one cm in diameter. Could be a collection of papules. Similar
potential causes as papules

Question 8

Papule

Answer 8

A solid elevation less than one cm in diameter.
 There is an influx of cells into the skin to create these lesions
 Consider bacterial and fungal disease, ectoparasites (demodex, flea bite, fly bite and mosquito hypersensitivity, scabies, immune diseases (e.g. Pemphigus), drug reaction

Question 9

Pustule

Answer 9

A small, well circumscribed area within the epidermis. Pustules are most commonly filled with neutrophils but are occasionally filled with eosinophils
 Consider bacterial and fungal infection, demodicosis, autoimmune diseases such as
pemphigus, sterile pustular diseases. If eosinophilic, consider parasites, contact sensitivity,
immune disease

Question 10

Vesicle

Answer 10

A small area within or below the epidermis less than 1cm diameter and filled with a clear fluid. Extracellular fluid is accumulating within or below the epidermis.
 Consider immune mediated skin diseases, congenital diseases, autoimmune subepidermal
blistering diseases, viral disease, epitrichial cyst

Question 11

Bulla

Answer 11

Area within or below the epidermis more than 1cm diameter and filled with a clear fluid.
 Consider similar diseases to vesicles

Question 12

Wheal
- what is it?
- what is angioedema?
- hives?

Answer 12

A raised, well demarcated edematous lesion that appears and disappears within minutes to
hours. Will blanche on diascopy. A huge edematous area affecting eyelids, face and pinnae are termed angioedema. Smaller papules are often termed hives and can be difficult to differential from papules
 Consider hypersensitivity (insect, drug, food etc.)

Question 13

Nodule
- what is it, how it is usually created
- consider what diseases?

Answer 13

A solid elevation more than 1 cm in diameter that extends into the deeper tissue layers. Cellular infiltration usually creates this lesion although calcification and fat can also do so
 Consider neoplastic disease, fungal disease, bacterial disease, sterile granulomatous diseases, calcinosis circumscripta

Question 14

Tumor

Answer 14

A large mass in the skin or subcutaneous tissue. Usually, a large influx of inflammatory or neoplastic cells

Question 15

Alopecia

Answer 15

Partial to complete hair loss. Can be a result of self-trauma or follicular disease which can be congenital, hormonal, immune mediated or infectious in origin)

Question 16

Scale
- what is it? consider what diseases?

Answer 16

Accumulation of loose fragments consisting of the horny layer of the skin
 Consider any chronic infectious/inflammatory process, follicular dysplasia, idiopathic
seborrhea, ichthyosis, sebaceous adenitis, nutritional disease such as zinc responsive
dermatosis

Question 17

Follicular cast

Answer 17

An accumulation of keratin on the hair shaft.

Question 18

Fronds - consider what diseases?

Answer 18

multiple hairs with large casts - have a paint brush appearance.
 Consider sebaceous adenitis, Vitamin A responsive dermatosis, demodicosis dermatophytosis

Question 19

Crust
- what is it? causes?

Answer 19

Adherence of dried exudate containing serum, blood or pus and scales. Can be primary or secondary and due to many causes, that include metabolic epidermal necrosis (hepatocutaneous syndrome), zinc responsive disease, any disease or self trauma that leads to hemorrhage

Question 20

Hyperpigmentation - most commonly associated with what?

Answer 20

A result of increased melanin in the skin. Most commonly associated with chronic inflammation

Question 21

Comedo
- what is it? consider what conditions?

Answer 21

A dilated hair follicle filled with corneocytes and sebaceous material. A blackhead or whitehead
 Consider feline acne, Schnauzer comedo syndrome, endocrinopathy, demodicosis

Question 22

Epidermal collarette

Answer 22

A shallow scaly ring. Consider a vesicle or pustule where the roof has ruptured
 Most commonly associated with bacterial infection, but fungal disease and immune mediated
disease needs to be considered as well as insect bite reactions

Question 23

Erosion
- what is it? causes?
- what is excoriation?

Answer 23

A shallow epidermal defect
 Consider self trauma as the most likely etiology but parasites, allergies and immune disease should be considered as possibly underlying cause. Excoriations are erosions secondary to self trauma

Question 24

Ulcer

Answer 24

Full thickness loss of the epidermis revealing the underlying dermis

Question 25

Lichenification
- cause?

Answer 25

Thickening of the skin resulting in exaggerated skin surface appearance. Generally, an indication of chronicity. Consider: chronic trauma

Question 26

Callus

Answer 26

Thickened skin most commonly associated with pressure points

Question 27

Fissure
- where do we see these?

Answer 27

Linear cleavage of the epidermis. More commonly associated with regions of moment with
a skin that is inelastic or seen at mucocutaneous regions (ocular, nasal, oral, anal)