dermatology 1 microscopy and terminology

Question 1

Layers of the epidermis

Answer 1

Stratum corneum = no nuclei, just keratin
Sratum granulosum
Stratum spinosum = thickest part with polygonal cells
Stratum balase

Question 2

What are the antigen presenting cells in the epidermis

Answer 2

Langerhans cells

Question 3

What is the adnexa

Answer 3

Glands and follicles

Question 4

What is the thickest layer of the epidermis

Answer 4

Stratum spinosum

Question 5

What is anogen and what are the microscopic characterisrics

Answer 5

Active phase of hair growth
See hair bulb is deep in dermis
Long hair shaft

Question 6

What is catagen

Answer 6

transition phase between anogen and telogen

Question 7

What is tenogen and what are the microscopic characteristics

Answer 7

Resting phase in hair cycle.
Follicle short and bulb superficial
Old hairs pushed out

Question 8

In endocrinopathies affecting the skin, what hair cycle phase are most hairs in

Answer 8

Tolegon

Question 9

WHat do we see with parakeratotic hyperkeratosis

Answer 9

Scale, flaky skin
Due to fragmented keratinised cells
Get increased thickness of stratum corneum with nuclei retained in stratum corneum
e.g can get this in zinc responsive hyperkeratosis

Question 10

What processes are epidermal hyperplasia assocaited with

Answer 10

Chronic dermatitis
Callous formatino

Question 11

What is acanthosis

Answer 11

Thickening of epidermis particularly of the stratum spinosum e.g in papilloma

Question 12

When might we see epidermal atrophy

Answer 12

Hyperadrenocorticism
Ageing
Malnution

Question 13

What is lichenification

Answer 13

Rough, thickened skin with fissures

Question 14

What do we see with seborrhoea

Answer 14

erythema, hyperkeratosis, lots of scbum, canathosis

Question 15

What is seborrrhoea sicca

Answer 15

Dry version of seborrhoea

Question 16

What do we call a fluid filled cavity in/beneath epidermis that is >5mm in diameter

Answer 16

ampulla

Question 17

What do we call a fluid filled cavity in/beneath epidermis that is <5mm in diameter

Answer 17

vesicle

Question 18

WHen might we see veicle formation

Answer 18

Viral infection e.g orf
Autoimmune disease

Question 19

What is the difference between an erosion and an ulcer

Answer 19

Erosion = partial loss of the epidermis
ULcer = loss of epidermis

Question 20

What is hydropic degeneration and when might we seeit

Answer 20

Intracellular oedema of cells
Can be seen in viral diseases e.g pox or thermal damage
If they merge, get vesicle formation

Question 21

Papule vs pustule

Answer 21

Papule = elevated firm area
Pustule = elevated superficial accumulation of pus

Question 22

When deficiency can lead to loss of pigmentation

Answer 22

Copper

Question 23

What is a fissure

Answer 23

Linear crack or break in dermis

Question 24

What is calcinosis cutis

Answer 24

Calcium deposits in the dermis e.g in hyperadrenocorticism

Question 25

What is calcinosis circumscripta and when might we see it

Answer 25

Calcium deposition in skin over pressure poiints Seen in large dogs with inappropriate lying environment

Question 26

What is perivascular dermatitis usually related to

Answer 26

Alergic skin dermatitis e.g FAD, atopy, food allergy, contact dermatitis, photosensitisation

Question 27

What is acantholysis and what disease might we see it in

Answer 27

Separation of the cells of the stratum spinosum layer e.g in pemphigous foliacous; with loss of monofilament desmosomes

Question 28

What disease might we see pigmentary incontinence in

Answer 28

Lupus erythematosus

Question 29

What is panniculitis

Answer 29

Inflammation of the subcut fat

Question 30

Endocrine skin disease characteristics

Answer 30

Hairs arrested in telogen Therefore easily epilated by licking/rubbing Bilaterally symmetrical alopeci EPidermal atrophy and hyperkeratosis Sebaceous gland atropgy

Question 31

If an animal presents with intesnsely pruritis facial nodules and has travel abroad history what might we suspect

Answer 31

Subcutaneous dirofilariosis = nematode spread by mosquitos with lifecycle under the skin

Question 32

Classic distribution of pruritis with cats with food allergy dermatitis

Answer 32

Head

Question 33

Classic distribution of itching with cats with flea allergy dermatitis

Answer 33

Caudodorsal and caudoventral areas HEad

Question 34

Classic distribution of itching with feline atopic skin syndrome

Answer 34

Head Ventrum

Question 35

What is a pustule

Answer 35

Small circumscribed elevation of epidermis filled with pus

Question 36

Why do we want to work out whether pustules are follicular or not

Answer 36

Follicular pustules e.g folliculitis need more severe treatment compared to non-follicular noes

Question 37

Example of cause of non-follicular pustules

Answer 37

Puppy pyoderma

Question 38

What condition are follicular cast often associated with

Answer 38

Demodicosis (can also get primary genetic defect causng seborrhoea in young dogs)

Question 39

What are follicular casts

Answer 39

Where hairs are held together by hyperkeratosis; often assocaited with demodicosis

Question 40

What is ictheosis

Answer 40

Primary seborrheic skin condition that can be seen from puppihood

Question 41

What mite do we need to get down to capilary bleeding to find

Answer 41

Demodex

Question 42

What might we use acetate tape impressions to pic up

Answer 42

Surface mits e.g cheytiella Bacteria Malassezia

Question 43

Where should we take a trichogram from

Answer 43

Lesion periphery

Question 44

What is wood's lamp used for

Answer 44

Identification of microsporum; makes hairs fluoresce bright green

Question 45

How long do we need to do an exclusion diet for and what do we do

Answer 45

Minimum 4 weeks Either novel foodstuff single source of protein and carb or commercial hypoallergenic diet

Question 46

How long must a patient be free from steroid or cyclosproine before intradermal skin testing

Answer 46

4 weeks

Question 47

How common is contact dermatitis

Answer 47

Rare