dermatology 1 microscopy and terminology Flashcards
Layers of the epidermis
Stratum corneum = no nuclei, just keratin
Sratum granulosum
Stratum spinosum = thickest part with polygonal cells
Stratum balase
What are the antigen presenting cells in the epidermis
Langerhans cells
What is the adnexa
Glands and follicles
What is the thickest layer of the epidermis
Stratum spinosum
What is anogen and what are the microscopic characterisrics
Active phase of hair growth
See hair bulb is deep in dermis
Long hair shaft
What is catagen
transition phase between anogen and telogen
What is tenogen and what are the microscopic characteristics
Resting phase in hair cycle.
Follicle short and bulb superficial
Old hairs pushed out
In endocrinopathies affecting the skin, what hair cycle phase are most hairs in
Tolegon
WHat do we see with parakeratotic hyperkeratosis
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
What processes are epidermal hyperplasia assocaited with
Chronic dermatitis
Callous formatino
What is acanthosis
Thickening of epidermis particularly of the stratum spinosum e.g in papilloma
When might we see epidermal atrophy
Hyperadrenocorticism
Ageing
Malnution
What is lichenification
Rough, thickened skin with fissures
What do we see with seborrhoea
erythema, hyperkeratosis, lots of scbum, canathosis
What is seborrrhoea sicca
Dry version of seborrhoea
What do we call a fluid filled cavity in/beneath epidermis that is >5mm in diameter
ampulla
What do we call a fluid filled cavity in/beneath epidermis that is <5mm in diameter
vesicle
WHen might we see veicle formation
Viral infection e.g orf
Autoimmune disease
What is the difference between an erosion and an ulcer
Erosion = partial loss of the epidermis
ULcer = loss of epidermis
What is hydropic degeneration and when might we seeit
Intracellular oedema of cells
Can be seen in viral diseases e.g pox or thermal damage
If they merge, get vesicle formation
Papule vs pustule
Papule = elevated firm area
Pustule = elevated superficial accumulation of pus
When deficiency can lead to loss of pigmentation
Copper
What is a fissure
Linear crack or break in dermis
What is calcinosis cutis
Calcium deposits in the dermis e.g in hyperadrenocorticism
What is calcinosis circumscripta and when might we see it
Calcium deposition in skin over pressure poiints
Seen in large dogs with inappropriate lying environment
What is perivascular dermatitis usually related to
Alergic skin dermatitis e.g FAD, atopy, food allergy, contact dermatitis, photosensitisation
What is acantholysis and what disease might we see it in
Separation of the cells of the stratum spinosum layer
e.g in pemphigous foliacous; with loss of monofilament desmosomes
What disease might we see pigmentary incontinence in
Lupus erythematosus
What is panniculitis
Inflammation of the subcut fat
Endocrine skin disease characteristics
Hairs arrested in telogen
Therefore easily epilated by licking/rubbing
Bilaterally symmetrical alopeci
EPidermal atrophy and hyperkeratosis
Sebaceous gland atropgy
If an animal presents with intesnsely pruritis facial nodules and has travel abroad history what might we suspect
Subcutaneous dirofilariosis
= nematode spread by mosquitos with lifecycle under the skin
Classic distribution of pruritis with cats with food allergy dermatitis
Head
Classic distribution of itching with cats with flea allergy dermatitis
Caudodorsal and caudoventral areas
HEad
Classic distribution of itching with feline atopic skin syndrome
Head
Ventrum
What is a pustule
Small circumscribed elevation of epidermis filled with pus
Why do we want to work out whether pustules are follicular or not
Follicular pustules e.g folliculitis need more severe treatment compared to non-follicular noes
Example of cause of non-follicular pustules
Puppy pyoderma
What condition are follicular cast often associated with
Demodicosis
(can also get primary genetic defect causng seborrhoea in young dogs)
What are follicular casts
Where hairs are held together by hyperkeratosis; often assocaited with demodicosis
What is ictheosis
Primary seborrheic skin condition that can be seen from puppihood
What mite do we need to get down to capilary bleeding to find
Demodex
What might we use acetate tape impressions to pic up
Surface mits e.g cheytiella
Bacteria
Malassezia
Where should we take a trichogram from
Lesion periphery
What is wood’s lamp used for
Identification of microsporum; makes hairs fluoresce bright green
How long do we need to do an exclusion diet for and what do we do
Minimum 4 weeks
Either novel foodstuff single source of protein and carb or commercial hypoallergenic diet
How long must a patient be free from steroid or cyclosproine before intradermal skin testing
4 weeks
How common is contact dermatitis
Rare
